The silly thing is that I've been the same when I started. A high energy kid playing around and celebrating everything fresh and new, with a big ego.

Probably a bad habit trying to stop them, they need to learn walking before they can sprint. The question is always how to put limits on them? I say it's overengineered, they say it's modern code and I am old. So what do you do if they send you a PR that is just plain wrong? I mean it seems like you delay the conflict from upfront design/planning to pull requests.

I have been in two different situations:

* Functional teams (established companies): enough seniors are here to tell the juniors when they are wrong, and the juniors naturally accept the criticism because it's expected in that environment.

* Dysfunctional teams (startups): most devs are juniors anyway, there is no clear hierarchy, managers are still at their first job so they have never seen a functioning team or had a competent manager themselves.

In the second case, there was absolutely no way I could win an argument: the "high energy kids with big egos" never believed me, I was the "old guy" as you mention. I remember an example where the "kid" failed and gave up with their "right" way after 3 months and I solved it in 3 days, exactly how I had suggested they did it in the first place. Next discussion, nothing had changed, they still knew better.

I can't really blame them, because the whole environment was like this. Everybody was always right, knew better, etc, even though it was their first job.

What I've learned is to protect myself and move away from that. Either by changing job, or by changing project. In startups I have been pretty successful at saying "I can help with this project if we do it this way, but if we do it that way, I can't help and I will work on something else". Of course it meant that I could not work on the most exciting project, but they made a mess out of them, so all in all I feel it was better working on my boring, stable, maintainable components.