The Introspective Pug is a wistful little guy. It started off with a picture of a pug looking dejectedly out a car window. People have since put captions on it making the cute little pug seem to contemplate the meaning of his own existence. The Introspective Pug meme usually starts with the caption "I don't know man..." and continues from there.
This is a compilation of the very best of the Introspective Pug meme. Be sure to check out Ranker's other meme lists like the Best Socially Awesome/Awkward Penguin, 25 Greatest Memes of 2010 and the 20 Greatest Misheard Lyric Videos.