Is there any person that lost lots of money by waiting for only 1 confirmation?
Not sure how much it will cost in the computing power but to reverse a tx with only 1 confirmation it will cost good amount of money. So maybe it's not worth to try for few bitcoin. Quote
Because I've heard that a 51% attack has never happened before.
This is where we stand. Source : https://btc.com/stats/pool?pool_mode=all