Most of the GAs I give fall into one or more of the following categories:
Accurate answer to an objective question
Nailed the answer. But only to the first person in the thread to provide it; I’m not going to GA people who come along later and say the same thing. Also, if it’s a pretty easy question and the accurate answer already has a few GAs, I’m not going to add more just because the answer’s right.
Lovely human being
Displayed grace, compassion, gratitude, forbearance, humility, patience…
Rhetorical skill
A point artfully made
Nice bit of prose
Good wordcraft
Went above and beyond
Did some impressive research, dug deep for an obscure fact, or otherwise really went out of their way.
Made me laugh
But not at someone else’s expense.
Social gesture
Sometimes a GA is just a little friendly nod to someone you’re engaging with on a thread.
Promising new user
I often GA decent comments from a new user just to encourage them to stick around.
Fairness
This is a GA meant to correct imbalances of lurve in a thread. You know, the perfectly good answers that haven’t gotten the recognition they deserve. It sucks to have given a good answer, and then watch as the lurve falls all around you.