In my experience, there's two ends of the developer spectrum.

At one end is uptight. They have all their shit on lockdown and the confidence that comes with that.

The other end is creative. They are developers because they enjoy creating, and development is a rare high-paying but creative outlet. They stumble through everything and get bored with reading too much documentation.

I have seen many cases of both of these, and another, underlying metric is their perception of their own intelligence.

It's unfortunate, but a lot of them grew up in an environment where they were the smartest person in the room and were rarely challenged. Now, being in an environment with many other smart people, they only feel smart by making others feel less than.

They purposely show off their knowledge and when you give an idea they shit on it and make you feel stupid.

There's also this thing where if you know a system really well, it's hard to imagine someone not having the knowledge you have. This is just how memory works because our brains abstract things away and then we can't recognize when others don't have that abstraction yet.

This is all normal. Humanity has a lot of work to do to change this, but it's embedded into how everything works, so it's not going to happen in our lifetime. You can change you, but you can't change anything else.

With that being said, here are some things I have learned, being from a similar background as you:

1. Recognize that you are smart or you wouldn't be there.

2. Accept that others will make you feel stupid. The best response is to act like it doesn't phase you.

3. Don't make others feel stupid if you can help it.

4. Be enthusiastic. Any shortcomings you may have, will be forgiven if you show up with a big smile on your face.

5. Talk to your managers. Ask them what would make you better at your job, and ruthlessly pursue bettering yourself. This will give you a lot of confidence.

6. You will lose touch with your old party friends. They will die young, and you will feel sad. When you do get a chance to catch up, talk to them a lot and consider journaling it. This will help a lot when you lose them.

7. You will feel guilty because you are doing so much better than them. Accept it and move on and try not to brag about your new life.

8. You will feel out of place because your new friends don't have the same background as you. Accept it and move on. Nobody else is worried about it.

9. Your new friends will probably not be as interesting as your old friends, and you will feel yourself becoming less interesting. This is the price we pay for our new life. If you want to stay interesting find a way to be in touch with other creative people: musicians, teachers, English majors.