I relate to this entirely. Once in a while, I'm hyped to do a raid and I'll plan ahead with my clan, but most of the time, I know I can't be on more than an hour, so I don't bother wasting their time or mine figuring out what to do. I just get on and do whatever is next for my character. Sometimes my clan mates turn up and fight along side me for a while and then wave good-bye, and that's fine. But most of the time I'm just enjoying an hour of downtime I've unexpectedly found that evening.