Total darkness...I once had to sleep in a loft bedroom that had no windows. I burnt a candle....but still kept waking up to check how much was left of it.
Aside from that...drowning is a fear......I can't swim,and this fear surfaces during air flights when I worry about the plane crashing into the sea.
NoM... it was the holiday from hell... the bonnet of the car came off (don't ask) and it cartwheeled down the M4 behind us causing mayhem... rain for 2 weeks... almost drowning... losing the dog for 3 days... parents having a big bust up and not talking for the first week... my sister breaking out in strange lumps on the first night in some sh!tty B&B and vomiting copiously all over me...