Does one have to attend both the bachelorette party and the bridal shower?

If you are invited to both and you are a close friend (some relatives are friends) it is your choice. If the Maid of Honor has the poor taste to invite the same group to the Bridal Shower and the Bachelorette Party and the above does not apply, it is your call. Personally if the latter were the case, I would not attend.