A Classic Paulism!

this evening I was washing up some dishes & need some more hot water. I turned on the tap & cold water came out...let the tap run for a few mins, stil cold water. Having not long had a bath & used the washiing machine I thought I'd used up all the hot water. I left it a while to let the water heat up again. 1 hr later still cold water. i checked my boiler was on etc. become puzzled at this point & left it again.  2 hrs later going to fill my kettle to make some coffee I'd realised I'd been turning on the cold tap all the time! Doh me!