Trust in a codebase can vary from module to module and is very fragile. I’ll go into more detail of what I mean with trust and how to determine the level of trust you can have in a certain piece of code.
Especially when programmers don’t agree on how variables and classes should be named.
In my current job, I’ve heard dismissive talk about testing. Along the lines of “well, that’s cute that you did that, now get back to work”. Work being manual tests to make sure everything works as intended.
Common goals bring us closer together whereas individual goals drive division.