Possible Duplicate:
In Civ 5, are Declarations of Friendship worth it?
Being somebody's friend is good because it gets you better trade agreements. Super. But it's also dangerous, as I've experienced too many times, because if my friend ever find a reason to denounce me then suddenly everyone hates me. Because of this I rarely accept friendship requests any more, and I never offer them myself.
Plus, friends tend to ask for favors once in a while. :(
My question is, in which situations would I want to be somebody's friend? Should I try to make friends with warmongering civs that wouldn't frown upon my warmongering? Should I try to become friends with far-away civilizations that are unlikely to find any reason to denounce me? Should I prefer to be friends with a stronger civilization, or a weaker one? etc.