I'm in agreement with tsl.
I recognize your phases, though. I've been through them all. I keep it semi fresh and interesting by varying my route home (I usually dilly-dally until it's too late to go any way but the most direct route, riding in) and I'll change bikes between the three I like the best: the touring bike, with drops and brifters; the hybrid with flat bar and big cushy tires; and the new build with the mustache bars and friction bar ends. Which one I choose depends on my mood, and how much time I have to move my MS headlight from one bike to another.

Lately, we've been so slammed at the library that I often ride one of the shorter rides back (even then it's such a great way to decompress that I'll sometimes change my mind half way home and switch to a more meandering route).