9 Things I Learned at 30

1. Speak Less, Listen More

If what you want to share with a friend takes more than a minute to say out loud, consider writing it down or recording it. I’ve found that good listeners are rare. While most people can chime in with polite nods and acknowledgments (like Japanese aizuchi), they often forget what was said just 30 seconds ago.

Part of this is because spoken words easily lose information in transit; part of it is that many people simply don’t care to listen. This became clear to me during several recent conversations. The game a friend recently bought, life updates, what their pet is named—gatherings end up just rehashing the same topics.

This also comes down to how much you matter to the other person, or perhaps they just don’t want to invest mental energy in you.

Another point—and perhaps a more important one—is that past thirty, you’re no longer considered young. It’s easy for your words and actions to turn preachy. If you talk too much, younger people might feel too polite to interrupt, even though they couldn’t care less about your accomplishments or stories. As the Japanese saying goes: “Mi no hodo wakimaero” (know your place).

It’s a different story if the occasion is a consultation or someone asking for advice, but at this stage in life, the best return on investment is holding your tongue. If there’s something you want to say, write it down, or turn it into a video or podcast.

2. Don’t Try to Change People

It left a deep impression on me: a few years ago, there was a colleague on our team whose working style was vastly different (omitting details here), making working together quite painful.

Back then, I couldn’t stand someone slacking off and dragging down the team’s progress. I tried many approaches: proactively pointing out mistakes in code reviews, nudging them on Slack about details, checking in on delayed and unresponsive pull requests—yet nothing worked.

My realization back then was that I wasn’t good at lecturing or changing people, nor did I have the kind of personality that easily mingles and blends in with others. So whenever I wanted a teammate to do something, my tone often came across as a bit aggressive.

My former manager once earnestly told me: don’t try to change people; assume people cannot be changed. Instead, understand their background and culture, and try to support them. He also pointed out that my actions weren’t actually helping the team’s output.

Looking back, what my manager said was profoundly true; unfortunately, I didn’t grasp it at the time.

People only change when they want to change. If someone falls short of requirements or expectations, either address it through systems and processes, or let team culture influence them gradually over time. Blame is the least effective approach.

3. Aim Lower

Whether dealing with yourself or others, the way to increase output is to lower your expectations. When you expect nothing from others, there’s no expectation gap. For yourself, it means avoiding the mental drain of holding impossibly high standards.

4. Begin with the End in Mind

Before buying something, never look only at the sticker price; take maintenance and ownership costs into account as well.

For example, buying a car in Japan is cheap and can be paid in installments. But once you buy it, you’re hit with automobile tax, acquisition tax, gas, periodic inspections (shaken), maintenance, and the constant worry about accidental scratches.

On the flip side, you can buy things that are easy to resell—like a Fender electric guitar.

4. “No Money” and “No Time” Are Lies

The phrases “I don’t have money” or “I don’t have time” that we often repeat are fundamentally issues of priority.

When we say we don’t have time to exercise or learn new tech, the unspoken reality is: “These things just aren’t important enough.”

Similarly, saying we “don’t have money” usually means: “The marginal benefit of this expense isn’t enough to justify shifting my budget.”

5. Everything Is a Trade-off

Everything comes down to trade-offs; it simply depends on what you value at the moment. When you need to ship a product quickly, you inevitably compromise on quality, and vice versa.

Life is the same: where you live, how you live, what lifestyle and spending level you choose—they are all trade-offs.

6. You Can’t Discuss Ice with Summer Insects

Don’t debate people when the cognitive gap is too wide.

In most cases, the other party has no interest in having a dialogue or changing their stance; they just want to argue until you lose your temper. I specifically use the word “debate” here. If it’s just casual chatting and listening to their story, the mindset is completely different. Hearing voices outside your echo chamber is rare and valuable, but don’t try to change their minds with logic or reason.

The clearest example is educational background. Middle school, high school, university—the differences revealed by what school someone attended are quite distinct. While there are always exceptions, it holds true nine times out of ten.

Can this be changed through real-world experience after entering society? Of course, but it depends on luck. A lower level of education often reflects poor family finances or a complicated environment, making it much harder to escape that predicament.

This happens all the time on social media. For instance, when discussing cookie security: does the other person have adequate knowledge? Do they understand how CSRF works? Do they know how SameSite is used? When both sides aren’t operating from the same baseline of understanding, discussing cookie security becomes completely pointless.

It’s just like the Coinhive incident I wrote about before: if someone doesn’t understand the underlying code, their gut reaction will simply be that it’s guilty.

Devotion (the game) is also a tragedy born from cognitive gaps—and indeed the tragedy of many Chinese households. Parents wish for their children to become dragons and phoenixes, burdening them with heavy expectations from a young age; a father obsessed with Cigu Guanyin, and Du Meixin, who deeply loved her father. As mentioned in point 2, these are things outsiders can rarely do anything to change.

7. Luck Matters Immensely

Coming from an IT background, coding and engaging with new technologies has always been second nature to me. During the boom of SaaS, I was fortunate to ride the wave, enjoying not only better working conditions but also higher compensation compared to other industries.

Furthermore, I moved to Japan and secured a stable job before the pandemic. After COVID-19 hit, remote work took off. Jobs were hard to come by during the pandemic, and in the post-pandemic recovery, the rapid rise of AI has made it even tougher for entry-level software engineers to find employment.

If I hadn’t entered the industry earlier, I might be facing those exact same worries: stressing over how to land a job, how to gain experience. To me, that is pure luck.

8. Drop Your Ego and Be Outcome-Oriented

Especially in the IT industry, people often view making mistakes, asking for advice, or seeking help as shameful. When someone else proposes a better solution, some even become defensive or aggressively dismissive, questioning the proposal with an irrational attitude.

I believe a large part of this stems from ego—the fear of having their credit or authority usurped. So when others perform better, this mentality instinctively kicks in.

Thirty is an age where you have accumulated solid professional experience. At this stage, what matters more is exerting influence. This is also the biggest shift I’ve realized compared to when I was younger. Helping others, generously giving credit away, and focusing on how to achieve the goal will make life so much easier.

9. Protect Your Positive Energy

Have you ever met people where talking to them—even about nothing in particular—feels inexplicably draining? While with others, simply having a conversation leaves you feeling energized.

The former aren’t necessarily malicious, but their communication style often carries an invisible pressure that leaves you exhausted. Here are a few telltale signs:

• Self-centered: They don’t listen. To them, a conversation isn’t an exchange, but just waiting for their turn to speak.
• Complaining: Repeatedly venting about the same issues without any intention of taking action to change them.
• Subtle lecturing: Even in casual chats, they try to assert superiority—nitpicking your details or invalidating your feelings.
• Great at pointing out problems, but never moving past them.

Conversely, people who bring positive energy usually share these traits:

• Listening: Not just hearing words, but making you feel truly understood.
• Emotional safety: You can openly share failures or vulnerabilities without fear of being lectured.
• Thought-provoking questions: Instead of rushing to offer advice, they ask questions that help clarify your own thoughts.
• Beyond identifying problems, they are willing to get their hands dirty to solve them.