Your friend found a point where he was satisfied with what he got. Maybe his trading experience so far, about how many times he missed the opportunity to take profit made him think that if he could close the trade when he felt satisfied, then he could get consistent profit. So he realized that if he could control his greed then it could give him a good profit.
And I feel that the average trader experiences the same thing when it comes to controlling their greed. they learn from their experience that they can actually get a decent profit if they can control their greed and not trade beyond what they can afford.
Mistakes/Errors do make out that learnings and these learnings could really be gained through engagement and this will be giving out that kind of awareness on which its really that impossible that you cant be able to notice it out after how many times you've been able to meet up and experience on the same scenario on which it will be that common sense that you would really be needing up to adjust. If you wont be accepting these mistakes and wont really be making up such adjustments then you would really be that not progressing when it comes to skill enhancement or simply with your trading knowledge. It will really be always that necessary for you to be able to be profitable. Greed is something which do really comes out whenever we do hit our specific target or goal amount and those feelings do come out usually at the end.
If you cant be able to control it out then this do signifies that you do have that unstable emotional control on which this will really be that so crucial when dealing up with this volatile market because if you cant be able to assess yourself when it comes to this then you will be having that needing up that versatility on when it comes to adjustment on how to deal up with this space on which it wont really be that so easy. If you are really that not sensible into this manner then it will really be giving out that kind of disaster into your trading career.