"Never trade with less than 2:1 reward-to-risk ratio"; "Whenever I hear people using 2:1 R-R, I laugh"; "Breakouts don't work because the market ranges 80% of the time"; "Only trade breakouts, because the big winners will put you on top"; etc.
People use blanket statements like this in books and on forums all time time.
What do they all have in common?