It is a piece of art....YOU are not perfect...what you create will not be perfect.....we are human beings.....not machines....
Yes I get very angry with myself when I finish a quilt and see all the points that are not perfect, and the corners that do not meet, and some seams that are not super straight and maybe a fabric choice that was not exactly correct....but sewing that quilt filled my day, it gave me JOY, and the person you will give it to will NOT see those mistakes, they will be amazed at what you created and will see all the love inside the quilt.
Don't be so hard on yourself, this craft/art is a continually learning process