Will_Newsome pointed out the caveat that it's only good to admit errors when actually in error. I'd add a second caveat, which is that most of the benefit from admitting an error is in the lessons learnt by retracing steps and finding where they went wrong. Each error has a specific cause - a doubt not investigated, a piece of evidence given too much or too little weight, or a bias triggered. I try to make myself stronger by identifying those causes, concretely envisioning what I should have done differently, and thinking of the reference classes where the same mistake might happen in the future.