It's a question that can start as many arguments as it can have answers: what is it that makes something funny? Ever-trusty Wikipedia provides the definition of "the tendency of experiences to provoke laughter and provide amusement", but that still keeps things pretty vague. When it comes to who or what we're laughing at and why, the options are almost endless.
The existence of memes only makes this funny business even more confusing. On the one hand, we've become accustomed to the rigid formats and concepts that make up many of the popular types. On the other hand, meme culture has taken so many bizarre twists and turns since its inception that it is hard to predict what type of thing we will suddenly find hilarious next.
In times like these, the best thing we can do is go with the flow. We might not understand why so many people find one meme amusing, but that's OK. Our own niche of entertainment is somewhere around the corner.