Film does not remain consistent

There are a few things in "Anger management" that doesn't remain consistent. When Nicholson first comes into Adam's apartment and says he's moving in, he gives Adam a list of things he can't do. For example, he tells him to avoid rage-inducing substances such as caffeine, alcohol, nicotine, etc. But a little while later at the Heather Graham bar scene in Boston, Nicholson doesn't care that Adam is drinking. Same with when Adam finds Marisa and Nicholson together at the resteraunt, he walks with Adam up to the bar and orders them each a drink. And earlier on when Nicholson says he must accompany Adam to work, full contact, and he's with him at work that day. Later in the film when Adam is at work on the phone with Marisa telling her bitterly to follow Nicholson's advice about seeing other guys and he throws a calculator at a co-worker's head, Nicholson is not with him there that time.