I've done a lot of stand-up comedy and I can tell you that, short of running in traffic blindfolded, you could hardly find a more reckless, self-destructive activity. To have the moxie to do stand-up - and especially improv - (i.e. - not rattling off canned jokes) - you need two things. 1.) Intense anger. 2.) A pathological need for approval. The relationship between audience and stand-up doing improv is almost military - it's a battle. It's you against them - and you have to win - or die. If they smell blood, you're cooked. It was unbelievably intimidating at first, but after a while I grew comfortable and very, very open. When that happend, it became less a battle of wills and more an invitation to play. To achieve that level you do need to feel very safe, and dare I say it, confident.