This happens to me a lot. I make judgements and form opinions about things I know nothing about, only to realise later down the line what a nob I've been.
I'm ashamed to say that one of those things was public breastfeeding. I always thought I was a supporter of it, but would say things like 'you can easily be more discreet' and 'why can't women use muslins and covers ' etc etc. I know, I know. Stupid and awful. Now I'm breastfeeding my first DC I realise what an absolute boob I was (pun intended). I've not got the time, inclination or energy to make sure I'm wearing discrete clothing or to suffocate him with a muslin. If he's hungry, he's going to be fed, bottom line. I won't deliberately parade my boobs about, but I won't go out of my way to hide in a corner. Oh what a fool I was to think otherwise.
What are some things you formed an opinion about only to find down the line you had it so wrong?