DislikedMathematically:
1) Spread
2) Negative Compounding Effect. e.g. losing 1% and gaining 1% afterwards will not result in break even. Same thing the otherway around.
This will get worse the more you risk.
Psychologically:
1) Letting winners run
2) Cutting losses short
It's true that you can be profitabel with any winrate but frankly in over 5 years of trading I have never ever seen anyone making profits year after year on high winrate and ~ 1:1 risk reward ratio on average. Spread and compounding will have dramatic effects if you trade like...Ignored