A burglar smashing my window and then smashing up stuff in my kitchen, when I was living alone in a flat. I couldn't decide whether to just make a run for it out of the flat in my pyjamas or confront them. I didn't think that I could manage to sneak out of the flat and then unlock the communal front door in time, so decided to confront them, armed with a roll of...erm... Christmas wrapping paper. So I turned the lights on and yelled out. Turns out that there was no burglar, but I'd overloaded the kitchen wall cabinet with xmas booze. It had started to come off the wall, had tipped forward and one by one the bottles of spirits and wine were sliding out of the cupboard and crashing onto the floor.
The second worst time was when the cat woke me up by dropping a live mouse on my face.
The third worst time was having a hangover and my husband waking me up at around 7am for a shag.
Actually, number 2 and 3 are fairly interchangeable in terms of which was worse.