What happens when you don't number apartment doors

I was just thinking about this again today, how it can be really frustrating when you're trying to go to someone's place for the first time... the directions they have to give you to find their door, because there are no number, you know? So I just wanted to ask, what were the most ridiculous directions you've gotten when someone invites you over? Ever knock on the wrong door? Ever just get totally lost? What are the funniest things that have happened because of this non-numbering system?

Oh the hours wasted and stairwells worn down, everyone getting lost in apartment buildings.... :-P

I remember a friend who lived in a tall block of flats with no lift, but I usually found her door because the person opposite had put an old fridge out but had never got round to taking it downstairs. So I used to look for the fridge. And then of course one day it WAS gone, and after that I used to get it wrong all the time, which was a bit nervewracking as you could hear people yelling at each other etc etc on the other side of the doors & you definetly didn't want them to open it...fortunately she moved later on, this time to the top floor, so now I know to just keep going to the landing :)