Mistakes I Made at My First Job

I Messed Up From Day One

On my third day at my first company, I ran an UPDATE query on the production database without a WHERE clause. I thought it was the test server. Nope — the terminal prompt was red. It was production. My mentor came running over, and thankfully we restored from a backup, but the service was down for 37 minutes. Three days into the job and my name was already on a postmortem document.

(I can still feel the cold sweat running down my spine.)

I Didn't Ask Questions

When I didn't understand something, I should have asked. But I was afraid of hearing "you don't even know that?" So I struggled alone. I can't count how many times I spent 6 hours on something that would have taken 30 minutes with a quick question. Once, I misunderstood an API response format and spent 3 days writing code in completely the wrong direction. When I finally showed it to my mentor, all he said was "why didn't you ask?" I had nothing to say.

I learned later that senior developers expect juniors not to know things. What actually makes them nervous is when a junior doesn't ask and just struggles alone. Questions aren't proof of incompetence — they're proof of learning.

I Took Code Reviews Personally

When 14 comments showed up on my PR, my ego took a hit. "Am I really this bad?" I thought. The comment "maybe rethink this part" genuinely upset me. Looking back, that reaction was completely ridiculous, but at the time I was seriously hurt.

But about 6 months in, the review comments started to decrease. I'd naturally begun avoiding the patterns I'd been called out on, and my code quality went up. Code review turned out to be the fastest path to growth.

I Thought Overtime Meant Dedication

I stayed until 10 PM every night. I thought being the last one to leave would make people see me as hardworking. Nobody cared. When my team lead said "why are you working late every day? If you can't finish on time, you need to change your approach," I was shocked.

(Honestly, half of those late hours were spent watching YouTube. I think I just felt reassured by the fact that I hadn't left yet.)

I Said Nothing in Meetings

I thought juniors should stay quiet. Even when I had ideas, I swallowed them thinking "what do I know?" Later, I'd watch someone else pitch the same idea and get it accepted. About 3 months in, my team lead told me in a 1:1 "speak up more in meetings." After that, I started sharing my thoughts even if I wasn't sure — and nobody gave me grief for being wrong. It actually sparked discussions that led to better outcomes.

I Didn't Know How to Set the Right Tone on Slack

I once messaged a senior colleague "why did you write it like this?" and the mood got weird. It was pure curiosity on my part, but in text it read like an interrogation. After that, I switched to "I'm curious about the reasoning behind this part — could I ask about it when you have a moment?" Same content, completely different reaction.

I had no idea tone management mattered this much in async communication. A single emoji can change the entire vibe.

Looking Back After a Year

Rookie mistakes feel like a rite of passage that everyone has to go through. But repeating the same mistakes — that's a problem. After the DB incident, I developed a habit of always checking the prompt color before connecting to production. For question timing, I created my "15-minute rule." If I can't figure it out in 15 minutes, I ask immediately.

But this is just my experience, and every company has a different culture, so you have to adapt. One thing I'm sure of, though: it's way better to make mistakes and learn fast than to play it safe and never try. I'm not even sure anyone gets through their first job without causing at least one incident.