I seem to be able to hold it for a long time.

But we went to a newly opened coffee shop on a long ride recently and the guy asked what bicyclists want in the way of a general store / coffee house. I thought of all kinds of recommendations. It occurred to me later that I should have said, "a pit stop and an offer to fill our bottles with tap water." Sure, it's not a pound of coffee or a sale for his register, but a shop that did that would be on my "great places" list that I would definitely visit when off-bike, and certainly recommend to friends.

So next time you're in a convenience store, and the clerk fills your bottle and you use their potty, make sure you give them a big thanks, and then when you get home, either write a thank-you note to the manager or make a point of going back when off-bike and thanking them personally (and make sure you buy something.)