yep taking a shower really just sobers u up...
it even works with me when i`m 2 drunk ... sometimes
mostly throwing up works better
but anyways I think its because of its relaxing effects..
more importantly though cause its a sudden change of enviroment..
often u first experience a sort of cold shiver immediatly activating u
and making u awake.
(from my experience)
when I take a leek somewhere outside in the bushes or so.. I mostly get shiver...
u could kinda compare the shower shiver with that.. but with the water and all it just really clears ur mind