Water.

We cannot survive without it and in the "developed" world we control it in it homes.

Unfortunately it sometimes beats us. 

My toilet cistern has had a small seepage for ages and today I had planned to fix it. After a trip to the plumbing supply shop I set about replacing all the washers and the inlet valve.

It appears that it doesn't actually fit the toilet bowl properly and the bolts are at such an angle they are unlikely to ever produce a watertight seal. After much struggling, sweating and swearing it still leaks so the landlord will have to be involved to get a plumber.