<p>When I’m at dinner and realize I haven’t friended one of my good friends there yet, average acceptance rate <5 seconds. (Smartphones, I can’t.)</p>
<p>When I’m getting incoming friend requests, sometimes I see them, forget about them for a couple weeks, and then accept.</p>
<p>There was one guy from my high school I friended at the beginning of my senior year, active on Facebook, who accepted my friend request about two and a half years later.</p>
<p>(Trying to be nice to poor OP and provide at least one non-mocking answer.)</p>