I almost feel honoured: as of this post, I've had two whole trolls, in my blog's short life! :)
Seriously, though: if you're curious about what standards I use to accept comments (vs. deleting them--and I do indeed use the delete button, at need!), here they are:
1) Don't use any obscene language. I'd rather not have the *polite* readers' eyes and minds soiled by it; and this rule is absolute.
2) To quote Fr. Z, "think before posting", and "practice self-editing". Yes, it's a subjective judgment-call, but if I judge your comment to be not only mean-spirited, but knee-jerk and thoughtless, don't expect its life expectancy to be very long. Mean-spirited but intelligent posts will probably survive, though their composers can expect a scolding for their ill manners (and warnings that their further comments might suffer deletion if they prove incapable of self-editing).
3) If you *request* that a comment of yours be deleted, I'll usually be happy to do that for you (though Blogger usually lets you do that yourself).
4) Please don't log in as "anonymous", if you can help it; when you comment, you can pick a pseudonym (fake name) for yourself by clicking the radio button next to the choice "Name/URL" (right above "anonymous"); type your chosen name in the "Name" space which appears, and--if you like--type the URL of your webpage, etc., in the URL space (though that's completely optional). Having dozens of "anonymous" posters, all arguing with one another, gets pretty confusing.
Summary: don't be a troll. Life is too short to be one, or to put up with one.
As you were... :)