So to support Andrea's position on this, if you read a lot of material on peak performance and elite mindsets, you'll find that the top performers don't beat themselves up. They reinforce what they did well and then just say "that needs some work" or "I'll fix that" to the stuff they didn't do well. That's how they remain confident. One example I remember and always keep in mind is this one from Rickey Henderson which starts at 2:20 and ends at 3:17.
To a large degree it depends on your beliefs about trading et al, what you want to accomplish and what is your pursuit. If you believe that trading well, by default, will produce profits, then being rewarded by the market or a nod of approval from yourself when you mess up is extremely hazardous imo If making money is your pursuit, then throw yourself a party on any and all profitable outcomes... the bullet remains in the chamber.
Being nice to yourself and approving of your behavior are two different things. Being kind is always warranted. Most of us are very unkind inside our heads. And, we are mostly unaware of this. So, try to bring it to awareness. You can't fix something you can't see. If you are "screwing up"-- stop trading. Figure out what is going on or what you need to do to move forward. If you are kind, you can remain detached and clear. Both are important attributes to help you with your next step. If you beat yourself up, you feel bad, you likely spiral down, and you have just lowered your (adult) ability to deal with the situation. Example--if you are mad at your spouse, are you going to yell at them and punish them? Isn't it more effective to kindly and calmly discuss it? To me these are similar situations. Only with your spouse your words are EXTERNAL--outside of you for the world (or at least the spouse) to hear. Trading, our words are INTERNAL so they can be incredibly mean, and no one will know because no one will hear them.