I'm not terribly rigid, but do like a routine. I like feeling like I'm going in order, thing one, thing two, thing three, and so on, during the day. The one thing I especially like about my routine is that (weather permitting) I walk my little dog several times a day. Potty time can be out in the dog yard, but walk time is more about sniffing and enjoying the walk.
I also like following a routine (mostly) for the stability if offers. I come to expect myself to do certain things, like dog walking, cleaning, errands, and so forth.
I also have a hard time defining it, but I usually stick to a routine and it makes my life simpler.