Happiness is ... free wireless in your hotel room.
Of course, if your laptop has a metal case and the wireless is in the lobby and, while your room is the one closest to the lobby, it's not really that close to the lobby and you have to have your laptop slightly sideways on the desk and keep adjusting its orientation to make it work stably, it's more Advanced Happiness Substitute than anything else. Oh yeah, and the "having to be in a hotel room instead of my nice comfy house" isn't exactly happiness either. Still, free wireless and the kind of quiet that lets me code for a couple of hours uninterrupted isn't so bad.
On the other hand, I keep running into limitations in both my knowledge and the capabilities of the software I'm using. That is a sign I'm on the right track.