Learning to let go of your mistakes is a lesson crafters need to know about. If you get something wrong it's usually better to unpick your stitches than soldier on and be irritated by the mistake every time you see it. Which'll be every time you look at the finished article.
A case in point is this parrot cushion. I made it many years ago, inspired by a Kaffe Fassett book. I traced the larger parrots from pictures in the book, added some sunflowers from a photo in Country Living magazine and - because I like pink! - I added a pink sky. The result was this:
If you get to that impatient gotta-get-this-done stage, the best thing to do is ... nowt! Roll the needlepoint up (or the patchwork quilt or the knitted piece) and put it in a drawer. Leave it alone. For several days or weeks or months, however long it takes before you're ready to take it out again and give it the time it needs. Unpick what you're not happy with. Undo those rows of knitting or take out those patchwork pieces where the colour or pattern detract from your overall design.
You're making something you want to last for a long time, and something that reflects your personality and pleases you. So don't fudge it. Get it right.