How much is too much?

I'm not sure how much is too much but I do know when enough is enough!
They are short Sunday School teachers at church since they added a second hour of Sunday School. The call is WAY out there for more teachers and aides but I'm letting it go to voice mail. I'm already a teacher to my own kids 7 days a week, I take care of the house and all, and I volunteer with 3 LLL groups - I don't need to be teaching a Sunday School class also (even if it's not my own kids' class). I'm really enjoying my 1 obligation-free hour each week to just sit in a quiet church hallway and read parenting books. I sit on a chair in front of a bright window, turn my phone to ignore and read. It's been such a peaceful time these last 2 weeks, and last week there was the bonus hour since the kids went to Sunday School for both the 10 and 11 am services. With the exception of the 2 ten-year-old boys practicing hurdles for 15 minutes in the hallway that I sit in, I was TOTALLY uninterrupted. It sounds funny since I was in a church, but I was in heaven for those 2 hours.
If only my shoes had been more comfortable...
Needless to say, I'm refusing all requests to become a SS teacher at this time. And I'll refuse to become a Brownie leader too.