I have a very generous but strict methodology to waiting. If I'm meeting somebody out and they're late, I arrive and I'm usually five minutes. When my clock turns to the time we agreed to meet, they then have 30 minutes to show up. If they haven't shown up by then, I considering the arrangement cancelled and I go home.
If I have someone to talk to while waiting in line, or have something to occupy myself with, it isn't so bad. If neither of these things are present, I can last a few hours. It rarely occurs where I must wait in line more than 3 hours to get somewhere, so.
I'm extremely patient in public because it's just fun to be out and about. Sometimes at the store I'll get in one of the longer checkout lines just to have those few extra minutes of peace. The same's not true in private, though. It's okay if I waste my own time, but I'm not a big fan of other people wasting my time since I do my best to not waste theirs.