... why wouldn't he also buy him cool clothes and a cool haircut?
I was definitely expecting the haircut after they established that Will patronized a hip salon ... and given the fact that Marcus had that ridiculous probably homemade bowl cut.
He had a different haircut by the end of the movie. He still needed to appear pathetic when he took the stage. It was too early in the film.
Besides, the trainers were just the plot trigger to get Fiona to confront Will in the restaurant.
His haircut WAS really bad. And it wasn't much better at the end IMO. His "cool" walk at the shoe store was also the dorkiest thing ever.
Funny that Nick is blossoming into a bit of a movie star in his own right these days.
A haircut is a step beyond footwear. The kinda thing you generally seek parental permission for.
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There are two kinds of people in the world, those with loaded guns, and those who dig. You dig.