My favorite meme of all time is the spam-fueled classic, Lennyface. I enjoy this meme due to it's core nature of perversion, playfulness, and mystery.
My most current favorite would have to be Roll Safe. Even if it had risque origins, the meme it has blossomed into now is glorious, and is very enjoyable.
The first recognizable meme I ever came into contact with was Awesome Face. I remember encountering that little dude when browsing Flipnote Hatena. I couldn't stop drawing it, and one of my classmates told me it was a rage face, from rage face comics. And that is how my journey of memes began.
My favorite aspect of memes is the pure flexibility, content, and community. Millions of people face-to-face and on the internet band together to create, share, and consume memes. The humor can be practical, abstract, or even surreal, and many memes focus or ridicule things in real life.