For example if you are a developer and realise your project needs to engage another team NOW for a critical deliverable due in 3 months and you spend your time on this task then you run the serious risk of pissing off both your manager and the project manager.

Or for example putting together a prototype that shows how another teams work could be automated.

Or pointing out flaws/discrepancies of a high profile product. Or telling a senior manager how a project is really doing, etc.

The bottom line doesn't matter as much in terms of respect and career progress as it should. There is a misconception that you can get away from politics if you work for startups or smaller firms but that's just not the case.