Having replumbed the kitchen last year, I never got round to reinstating the outside tap. Hence today's task was to do so. Scrabling around inder the sink, I discover I can't swing a spanner without removing the sink's u-trap. As I undo the u-trap, I repeat to myself over and over... "I must not empty the U-trap down the sink." "I must not empty the U-trap down the sink." "I must not empty the U-trap down the sink." and sure enough, I just about managed to stop myself emptying the u-trap down the sink, and empty it outside the back door.
Most of the outside tap pipework can be soldered which I'm fine at. However, the connection to the internal isolating valve and the connection to the tap itself are compression joints, which I hate. Anyway, the soldering proceeds fine. The compression joints, as usual, leak. Some extra tightening improves this, but further tightening doesn't, and I'm now heading into the area where the joint will collapse before it ever became watertight. Since this is just a tiny drip, I decide I'll leave it to seal with hard water (that's one really handy thing about being in a hard water area;-).
Anyway, feeling pleased with myself, I tidy up and go to wash all the flux/copper grime off my hands. After a couple of hand washes, I suddenly realise I'm standing in a rapidly rising flood in the kitchen. The combination of references to what I think of compression joints mixed with swear words doesn't bear repeating here, as I quickly open the cupboard under the sink to turn off the main stop c*ck. Then I see where the water's coming from, and notice the sink u-trap is still sitting in the sink waiting to be reconnected -- that's the same sink I just had a nice long hand-washing session in...
Next half hour spent bailing out the kitchen and drying off everything in the cupboard under the sink.