"It's not giving up, it's disengagement." If you set out to do something and stop doing it before you've succeeded, even though you could carry on with at least some possibility of further and future success, calling it anything other than "giving up" is just sugar-coating it. I'm sure it's sensible and wise to give up in many circumstances, but giving it a fancy name really shouldn't be part of the process of justif…
If you make a goal at time t1 and decide at t2 that that goal was a hasty and thoughtless goal, then I think the person you are at t2 should be the person you evaluate yourself as, rather than clinging to statements you might have uttered in the past. Black and white thinking of "success / failure" is a good way to make sure everything in your life goes exactly as planned, while wearing blinders. You need a combination of both in order to really be successful.
Being mean to yourself doesn't necessarily lead to success. If you've only got a mile left in the marathon and you've already ran 25, yes, that extra mile is kind of important, but also, no, it really isn't.