You might show enthusiasm if you find out that all the shoes are on sale for 70 percent off today. The word enthusiasm indicates intense excitement.
The noun enthusiasm comes from the Greek word enthousiasmos, from enthous, meaning “possessed by a god, inspired.” It was originally used in a derogatory sense to describe excessive religious zeal. Today both the religious and derogatory connotations are gone from enthusiasm, but the zeal has survived. Use it to describe great excitement or interest, like what you feel when you’re doing something that you really, really enjoy.