For me, not dwelling on regret is pragmatic. I simply do not have the mental resources to fritter them away on the past mistakes or triumphs. Freewill is an illusion. (I don't mean that freewill does not exist, I mean that freewill is not what it appears to be.) What ever freewill we do posses is likely limited to a very small portion of pure thought. I try to use this valuable resource to set my intention for the future.