Blue or red door?

Yeah... The mistakes are learning experiences. They help us grow. If your mistakes are "I dated a girl who cheated on me" and "I leased an expensive car when I shouldn't have"... Those things probably helped shape you into a more rational, mature person, assuming you learned from them.

Now if your mistake is "I worked 80 hour weeks for 30 years for my shitty career and never saw my family and now I'm dying early from stress induced heart attacks" or "I had some shady dealings in the past and now the mafia is after my family", I'd take the mistake-fixing door. But hopefully most people's mistakes aren't quite that bad.

This is literally a nightmare I once had. I dreamt that I found a time machine and started changing my past little by little, working backwards and fixing minor mistakes, then bigger and bigger ones, but seeing no major impacts on my life. Like fixing a flunked exam only changed the diploma to a "with honors" one and nothing else. But I kept going until a certain event in my life that had really profound impact on my emotional health and made me attempt suicide, but it was also the one that really shaped me into who I am today. After preventing it, bam, Im in a place and a role the current me would've never wanted to be in, and the guy I turned into probably didnt want either, it was just so much worse off. After that dream I started to go much more easier on myself. I still cringe from time to time when I remember my past actions, but I dont really regret what happened anymore.