The biggest potential band-killer is what happens when the members have different goals. If someone is serious about making a career in music, they will get hugely frustrated in a band that just wants to amuse themselves, and play the ocaisional gig.

Second-worst band-bomb is the intrusive Significant Other. Girlfriends, wives, boyfriends, husbands, whatever - don't ever let 'em even think they have any kind of say in band issues.

There will always be a certain amount of ego-tension in any group of creative people. A certain amount of that can actually be beneficial, but be perpared to shut it down fast if it shows signs of getting out of hand.

A great band is composed of people who genuinely enjoy working together. Ideally, that means that everybody pulls their own weight, plus lending a hand to each other. It's all too easy to let someone else pack the gear, or load in/out, but don't let it happen. Bands have to function as a team; prima donas are deadly.