Bear's character is shown in the first five minutes of the movie.

I think Bear's attitude is shown to us at the beginning of the movie when he basically sounds angry with his cat "How did you get in here" as if it wasn't his fault leaving the medicine open or out on the table at a minimum. The next scene clearly shows us they didn't belong out in the kitchen when he puts them in his bathroom behind the mirror door.

He's such a coward he can't even give her the gift he bought her, so he ends up using it.

He could have stepped up and confessed his love to Nikki, changing the events.

He could have told his friends about the wish, even Sarah, convinced them with how she's acting, and easily gotten them to counter the wish before things got out of hand.

Bear is such a coward, not only does he fail to change things the proper way with honesty, he also consistently takes no responsibility for the consequences of his actions, from the first cat scene, which is why the movie continues the way it does.

Anyways no one in this movie is good, Ian lies to his friend and gives him bad advice at the start, Sarah texts her mentally ill friends boyfriend at 3 am and tries to meet up and kiss him, no ones the good guy here, but I think Bear's responsibility (or lack there of) is shown right from the start.