True, but I can't bring my tools (computer, etc) with me. And it's about a one-half hour train ride so i may be in the middle of something, and have to close up. It's the time pressure of having to finish up a complicated and important task that compels me to forgo catching a train or driving/cycling home. But it is satisfying to leisurely read the newspaper on the train.

Another dimension to my job is that within a great latitude i can coordinate my personal energy level with my tasks. For example I am an early riser (a "lark"), and if I stay over, I can be at my desk at 4:30 AM fresh, energetic, and uninterrupted.