Why do they have to break things?!

It's so annoying when you take on a bus and you want to adjust the temperature or something in the cab but you can't because some mong has broken the ruddy control knob. Why do some drivers have to wreck the cabs? Mind you it may have been done by shunters or engineering staff, but it can be frustrating. I hate it also when you take on a bus and the seat adjusters are broken, so you end up getting cramp or back ache because you can't set the seat right for your needs.