It's hard to just pick one but I'll mention one that I don't think get's enough attention: Working on external codebases. We all use frameworks and libraries t

It's hard to just pick one but I'll mention one that I don't think get's enough attention: Working on external codebases. We all use frameworks and libraries that are maintained outside of the company we work for. Those frameworks and libraries help us to do our job faster and it's fantastic that they are available to us. However, sometimes those external codebases cause a problem for us. The abstraction breaks or falls down. There's a bug in that external codebase. If no one at the company is capable of debugging and understanding that codebase then when the abstraction fails us a lot of time is wasted. It's also really good for a company to be able to contribute fixes to an open source codebase back. It's healthy for the open source project and in turn makes that project better for the company.