My first pull request was a bad experience. :(
In my company (practo.com) for the first task - I hardcoded few data in the php codebase itself (in a separate static data file) instead of having mysql table keep it. The use case was such it made sense to have data in php serialized array instead of table. I wrote a utility function to do the query. This was because it was done like this way before for similar problem in the code. I went through the code and followed this only.
But in code review - Response of team lead was : "You are good, you have to do it in better way. Don't follow existing code structure. This is why you are here - to improve things.. "
Eventually that bad code only went in prod. Lesson was: "Never go to seniors with just your problem, have a solution also so they can either validate your solution or give another one for you to think.." :)