Is taking a shower after a workout bad?

It is definitely not bad. Rumors might say that you would have muscle spasms or something like that but that is truly mistaken because muscle spasms occur when a muscle is overused and tired, particularly if it is overstretched or if it has been held in the same position for a prolonged period of time. In effect, the muscle cell runs out of energy and fluid and becomes hyper-excitable and then develops a forceful contraction. That said, it is not bad to take a bath after working out. Watch the movie "Wanted." After they assassinate, they go for the ice bath. See? It's actually a positive thing. :)