Power gaming:
http://www.geneticanomaly.com/RPG-Motivational/slides/powerleveling.html
many more good ones to be seen!
Damnit: http://www.geneticanomaly.com/RPG-Motivational/slides/change.html
There's seven D&D books in that picture, and I own or have owned five of them (still have four).
LOL
Heh!
http://www.geneticanomaly.com/RPG-Motivational/slides/sharedefeat.html
:D