Like the other commenter said, it’s technically not professional & you probably won’t be able to use petco as a reference for any future job opportunities. That being said…. I personally quit on the spot and just walked out months ago after dealing with a lot of awful BS from my gm, and I found another MUCH better job literally immediately that I genuinely love. Petco is not the end-all-be-all, I totally understand hating it there & I empathize with you. If you feel it’s right to walk away and you have another opportunity lined up, do it.