[jdsully]

The difference is whether the person is expected to manage the situation on their own. If I said that to a buddy of mine who I know works on his own car he would be upset. He imagines himself capable of working on cars and I just communicated I don't think he can handle it.

Nobody wants to be the person that other people see as a basket case. Just because someone is upset doesn't mean they can't solve the problem.

[jimmaswell]

You can make a scenario where anything is rude. Here, if he said something and you said "could it be the fuel pump" that should also be an inoffensive comment, not prompt him feeling like "how dare this fool presume to lecture me about the inner machinations of an automobile; let this mark the end of our friendship"

[olyjohn]

I dunno man, I think this is more for situations where people are having personal or emotional issues. Things that they might be trying to work through. Not for troubleshooting a broken car or computer.

[ljm]

Zen and the art of motorcycle maintenance explores exactly this beautifully.