It's fun to break away and draw off the wall stuff sometimes and you can learn even from those if you pay attention. This is just me, and it may not make much sense, but make sure you pay attention to the flow and balance of things. I think you did a pretty good job of that with your on the way home from work sketches, it shouldn't be neglected in your fun stuff either, if for nothing else than to keep from fostering a tendency that can be distracting in the more serious pics. Keep up the good work! It'll pay off in the end.
Oh, the inked head in the last pic is quite good too.