due to klutziness or inattention but I would not blame my pedals... what kind do you have? do you know they can adjust the tension? it shouldn't be so hard to clip out that you wrench your knee on a sudden stop, maybe the shop can loosen them a bit? Mine are very easy to get out of (speedplays).
I agree with you about groups and traffic, we just get more respect from cars when in a group than alone. During rush hour I still stick to the bike paths whenever possible rather than brave traffic... on weekends I'm a little more daring. I try to go on as many group rides as possible because I want to practice being comfortable in a paceline, there's a regular Sunday ride that is very good for that, we have a patient "leader"...
Good job on your hilly 33 miler! and good luck on the future 50 and 100, you'll do fine. If they are less hilly they might not even be as hard as the 33, who knows? (hills make a HUGE difference).
We don't have any local bicycle "events" like that over here, I wish we did. There are races but they are only for hard-core racers, which I'm not (and am too intimidated to contemplate ever being, never mind being too old to be competitive anyway). I get to hear about their exploits every Monday night in spinning class
I have to admit the thought has crossed my mind: could I do that? Nawwww...
There's a few centuries around here in late summer / early fall but none are exactly close by. People talk about the Seagull Century a lot - it's very crowded, hearing people talk, for some that's a good thing, for others that's a bad thing, for me, I'm not sure!
The only one I've done (Potomac Pedaler's) wasn't crowded at all and ended up being just a long ride with 2 guys I'd never met before. Maybe crowded is good?