On October 15, 2004, at 10:57 am, Michael said: "I like". It happened in a private forum, so I won't quote him in full, but it was something like "X did y. I like."

Normally, "to like" is a transitive verb, which means you need to specify what it is that you like. There are many situations, however, when using transitive verbs without an object isn't ungrammatical. Geoffrey K. Pullum even went so far, to conjecture that perhaps any transitive verb could be used as intransitive in certain situations.

"I like", of course, isn't such situation, it is a creative violation of the rules of grammar. That's why I like it.

And here is a promised quine:

I like "I like".