My favourite tool for serious work? Probably the stanley knife (I don't know if it has a different name across the pond) - you can use it to chop up just about anything reasonably accurately. Almost every job I've ever done has needed one...even jobs that you wouldn't normally expect, so I couldn't be without it.

On a more 'dopamine-inducing' level though, it has to be the biggest hammer-type-thing I can find in my shed every time. I had to get rid of an old wooden bed a while back, and I've never had quite so much fun 'doing it myself' All those bent iron nails and shattering shards of wood...home improvement heaven...

Yes. Nothing beats a bit of reckless destruction. Nothing.