The two main problems I have are in the winter, the glasses misting up when I go from somewhere cold outside to somewhere hot inside and in the summer, when I go from outside to inside and I have to stop and wait for my glasses to change from tinted to plain.
Otherwise.... I can't see what the hairdresser is doing when cutting my hair so on a few occasions have had a nasty shock when putting my glasses back on after a cut!
There are times when it's not so easy plucking one's eyebrows. I also dislike glasses not being clean and always carry lens cleaning towellets in the car. I find the brown coloured lenses in my prescribed sunglasses to seem to have more than their fare share of dust on the lenses even though they are always placed back into their case after use.