Have my cake and eat it?

I have noticed a worrying rise in my pessimism as of late.

I started off as a 'glass is half full' kind of girl. Almost to the point where I have similarities to ice cream - nice, but after a while, it starts to hurt your teeth. Then I started thinking 'but what if the glass is half full of something gross? Surly that's not optimism, it would be more optimistic to think that the glass is then half empty. So for a while, I was an optimistic pessimist. More recently again, I've become more of a realist. I know at the end of the day, someone is going to have to wash the glass.