In reply to Lupine Lacuna:
Started 20 odd years ago in a steel fabrication shop, making tea and sweeping up. Ended up as a duct fitter, then refrigeration engineer, then designer and project managaer. Jacked in that job and decided to go into sales for an easy life. Hated it. Had three jobs and hated my last boss so much I jacked it in and set up on my own 7 years ago.
My business has been very much getting projects (all still associated with air con, heating and vent) that my clients simply cannot do for one reason or another and they ask me. This can be anything from surveys, design work, CAD, estimating, project management but the best jobs involve lots of chin scratching and "hmm how shall we do that?".
Last 3 years or so I've getting into energy management and now work for a load of new clients (the recession wiped out most of my orginal customer base) including a couple of blue chip companies helping them reduce running costs and also helping them replace old knackered systems.
The absolute best thing and the reason I will never work of some else is I control what I do. I tend to try and find interesting or challenging jobs rather than looking at the money and I can always have a go at something I've never tried or I think may be a good opportunity.