One of my goals when learning a foreign language is to be able to introspect in that language. I think translating one’s thoughts, desires and sensations into a language other than the native tongue or English is an interesting exercise. It could also be a way to gauge one’s grasp of a foreign language. Because thoughts are spontaneous, being able to express these fluently would be an indication of proficiency.
Since I have been learning Japanese for some years now, I would sometimes attempt to think in Japanese. And then I would imagine that I am a character of some anime having a stream of consciousness. It makes the entire learning experience more fun.