Category errors

A handle is not a hook. If you use a hook as a handle, say for example to hang up your coat, that handle ceases to function as a handle and life becomes harder. 

A sink is not a storage space, it is a space for making things wet. If you use it as a storage place, by leaving mountainous piles of dishes in it, it ceases to function as a place for making things wet. 

Unfortunately my life is beset with people who make category errors.