Ignorance. Plain and simple. Popular usage has turned "captioned picture"  into meme. "Bad Luck Brian" is a meme "Overly Attached Girlfriend" is a meme "Scumbag Steve" is a meme It isnt a meme unless the picture, in and of itself conveys a message.  We know, just from seeing poor Brian's face, that the caption will involve misadventure. The caption just lets us know the specifics. We know the caption will involve somethinng crazy, psychotic, or needy when we see the overly attached girlfriends face. We know that that socially inappropriate behaviour will be described in the caption as soon as we recognize Steve, and his trademark hat. A PICTURE WITH A CAPTION IS A CARTOON. THE FAR SIDE IS NOT A COLLECTION OF HUNDREDS UPON HUNDREDS OF MEMES. /end rant.