I'm a scientist. I've probably said this before, if anyone reading this hadn't guessed already.
One problem with being a scientist by profession - and a research scientist at that - is that your job may well involve doing things that you think you're good at, but that only means you're not completely useless at (as we've only just worked out how to do it at all).
Which means you can spend two days on something and fail utterly. As I have done. So I'm rather annoyed right now.