I blame someone else for ruining my diet
Is this person the main reason for your diet not working out? If so, how will you respond?
No he's not, but I want to give him the finger
Losing weight can be a frustrating endeavor, but you have to be responsible for your health outcomes. Instead of giving the finger, you should do something constructive, like consulting a dietician.
I don't need to go out of my way to consult a dietician.
That was only a suggestion, but the point is that dieting will always be a long and arduous process, with ups and downs along the way. The important thing is to not get discouraged when things don't work out, and especially not to blame others. I'm sure you can do this if you just keep your mind on your goal.