This is me pretty much. I crush problems under my foot at work, and then leave after putting the requisite hours in.
I've had employers tell me to work more hours so they could bill our clients more. I was naive, and asked why, as my components didn't require all-day debug sessions at client sites, and I regularly hit my milestones. I didn't understand the perverse incentives that come into play when consulting. No doubt they wanted me to work on something; but all they saw was the dollar value I was worth. In the time I would have spent at the office, I arguably put it into something more productive (long-term), such as working on side projects, or practicing a musical instrument.
These days I consult at a strict 30 hours a week. I have workaholic tendencies, so I'm on a rest cycle WRT work.