Heck, nearly everything in a bathroom can be improved: faucets (re-adjust every time you use them, run water until desired temperature is reached); sinks (too shallow to do anything in, faucet gets in the way); medicine cabinet (reach over sink, too shallow so stuff falls out, fingerprints on the glass every time); toilet (cold, too low, smelly, spray goes everywhere, noisy); shower (curtain useless, water leaks out, run wasted water until warm, can't spray water UP at all, crowded for two or more) and so on.

Spider Robinson had a character in the Callahan's Saloon series that went into some detail on this.