why did you even let this person get away? doesnt matter if the thing was worth $1 or $100, it was yours. Personally if that had been me i would have been after that guy and make him think twice before stealing again
I can think of several reasons - of course with the hindsight of age - one of them being is the overall effort worth it?
The idiot(s) who did the bump and steal are obviously immature/ insecure bullies, and who would probably love someone coming after them so that they can once again prove their "superiority" by "defending" themselves.
Maybe next time, if there is one, careful vigilance can avoid the bump and a discreet foot can trip the assailant.