Saturday stuff

While having my second cup of coffee, this morning, I decided to have a blitz on the under-sink cupboard and promptly removed everything and set about cleaning the shelves. I chucked a few things out and cleaned the rest, then put it all back in nice and tidy.
I was cleaning the big sink and the little one beside it - perhaps I was a bit heavy handed but suddenly the drain and plughole of the little sink collapsed and a load of dirty water and gunge ended up where I'd just blitzed. Grrrr! Not happy!
To curt a long story short, had to remove everything from the cupboard again and clean the mess. Terry nipped out to buy a new drain and very quickly had the old one detached and the new one in place. I then put everything back in again!
What I want to know why, when you've spent an age cleaning and tidying somewhere,  does something mess it up again immediately?!
Not been out today except for a very brief spell in the garden - just looking to see if anything needed shifting eg rubbish and seeing what was flowering. The snowdrops are still going strong and the crocuses are nearly ready to open..