Never really. It's never worth it for me to fight with someone that won't have a reasonable conversation.
2) How often does an lj someone make a generally unprovoked for snipe at you?
Not often, particularly as I'm not very active in communities.
3) Do you belong to any communities with a high drama factor?
4) What's your theory on why there is so much raw rage on the 'net?
Anonymity + written word= stupidity. It also doesn't help that you've taken a lot of people who don't really interact well in social situations (thus the involvement on the net) and stuck them in one place. The self-image problems alone allow for serious misinterpretation of intent. This is not necessarily true of everyone, but the rule of bad apples seems to apply. Also, the deliberate trolling for reaction...
5) Are these high drama interactions a source of amusement or a nuisance?
It's like a train wreck - can't help watching, but it's no good for traffic.