One thing that really caught my attention is how reddit went from 'if you wear masks you are overreacting and a bad person' to 'if you don't wear masks you are killing people and a bad person' in a heartbeat.
I'm not advocating not wearing masks or anything, I was just surprised how the definition of what was the "obviously" right thing to do changed in a heartbeat without any concern on how diagonally opposite these two advices were.
When such opposite advices are given by the same institution I think some skepticism is really useful. (Did they know the previous advice was wrong in which case they lied? Did they not know any better but gave advice anyway? What was the compelling evidence to change their minds?). Again, I think you should wear masks, but the total lack of questioning and the instantaneous change of opinion I saw online was really weird.