I find I am very picky who I choose to follow or follow in return on Twitter. People generally put that which is most important to them in a prominent place in their profile and it is a great indication of what sort of things they will tweet about.
Anything remotely to do with politics with send me running away as it is a very personal issue with most people and I don’t find it interesting. Likewise, any mention of any sort of religion and I will head for the hills. This is a highly personal issue that is again, subject to opinions, which I don’t want to hear. Religious instruction has those people highly qualified to do just that and it is not a function of those on twitter.
Flames wars, or nasty, snarky comments are also a way to get unfriended. Don’t have time for negativity and never will.