Health.<p>If I program 9-5, go home, eat, program more, program some more, and then go to sleep, I get fat. Fast. My social anxiety mounts. Fast.<p>I need at least 1-1.5 hours a day of gym time, .5-1 hours cooking time, some social time squeezed in there somewhere. I <i>do</i> have side projects - but I don't have kids, and I don't have another hobby - what if I enjoyed woodworking, painting, writing, or music? Devote a decent amount of time to that, to your health, and to a 9-5 job, and squeezing a meaningful programming project in there starts to get difficult.