I try not to have a TBR pile because like you said I feel the "pressure". I love finishing a book and knowing that I can go into Waterstones the next day and buy a new one! If a book has been in my TBR pile I just lose the excitement.
I wasn't a big fan of the Harry Potter books to be honest. I read until half way through the 4th book and put it down... I don't know I just felt the story dragged a little