Srimate Raamanujaye Namaha,
Udayavar Swami, there is another perspective when we realize that it is our own actions’s reactions we are reaping. We feel we are not scape goat of others actions but we are ourself responsible for ourselves.
Also once we realize that we have committed mistakes, we can accept it humbly that we are prone to mistakes, such acceptance of our past and regret of the same would help us to be in goodness and then take positive direction of taking shelter of Achyutah.. (one who does not make any mistake and never forgets to give shelter to His devotees).
Just, lamentation which is is mode of ignorance is not helpful. But regret in mode of goodness is good. It can inspire and make one enthusiastic.