Much is written about trading as just getting a great entry and exit. You get in at 100, get out at 110. This is great, but in reality most people are afraid that they will get in at 100 and get out at 90 and keep losing money.
The fear of losses is behavioural and wired in our brains. It's easy to say that we should not think like that, but in reality you cannot avoid it - it's just the way we are. The greater the loss the more lousy we feel, largely . . .