I only am a grammar Nazi* when a person is being an idiot or it's impossible to understand what they're saying. When I say 'being an idiot' I mean leaving comments like:
"Your stupid!"
I respond with:
"My stupid what?"
*I don't mean to be a grammar Nazi or anything, but 'Nazi' is always capitalised because it's a proper noun.
I'd probably say my bad habits are:
Procrastination. TGC is a great source for that - I've been home with my parents since Sunday and I still haven't fully unpacked. I've got an interview at the Job Centre tomorrow and I'm supposed to be digging out documents for that, but here I am, procrastinating by talking about my procrastination. My excuse is that I'm waiting my MS Office 2010 upgrade to download, but then it
really isn't an excuse.
Biting my nails. Just because.
Nodding my head in a rhythm when there's no music playing.
Slipping into different languages at random. My standard response to something confusing isn't, "what the hell?" but "nande yo!" And if I don't understand I say, "ich weiss nicht!"
To make inappropriate sounds at inappropriate moments.
Coming onto people of the opposite gender, despite being straight. Usually I do it to straight guys, but I have made the odd mistake before now.