Guilty. Especially when the question is preschooler standard and they time out. My usual line is, "How could you NOT know that?!!" Luckily, at that time of day I am usually alone. As Jennifer says - it is annoying for others who may be watching.
Yep, all the time. And shout 'abuse' at the contestants when they say something utterly stupid! I sometimes wonder why they even bothered to go on the show when they obviously have NFI about almost everything!