Sometimes with mistakes, we thought we were doing the right thing at the time and we did not know any better. However it can be painful dealing with regret as we cannot go  back in time and change things. Mistakes can be capable of ruining our lives and we can be tortured by thoughts of what we could have done differently. For me the mistake was existing in the first place and I am not capable of dealing with this life for many more decades. For me, the right thing is death, as then life can not hurt me anymore.