vanblah

To clarify further:

"Nuts" is slang for someone with mental problems.

"Nuts" is also slang for testicles.

The humor also plays on the fact that "your" and "you're" sound the same but have entirely different meanings. It's difficult to convey this joke in written form ... but it works. For instance, if he'd said, "I can clearly see YOU ARE nuts," instead of using the contraction "you're" the joke would have no real humor to it other than the visual image of someone dressed only in clear plastic wrap. And let's face it, that image is just not very funny.

The joke also plays with grammar in that it uses a split infinitive to drive home the image. For instance, if the psychiatrist had said, "I can see your nuts clearly," or "Clearly I can see you're nuts." the joke would have less humor. In these examples, although they can be considered funny, we are de-emphasizing the word "clearly"; some people might even ignore that word since it is placed at the beginning or end of the sentence. By splitting the infinitive "I can see" we are emphasizing the word "clearly" and calling attention to the fact that the man is wrapped in clear plastic wrap and the psychiatrist can, in fact, see the man's testicles.

The joke is also funny because a man dressed only in clear plastic wrap appearing in public may also have mental problems.



PS: Saran Wrap is a very popular brand of clear plastic wrap used for food storage, at least in the U.S.