On the 100th episode clip show, they showed the clips of the "Wrong-sounding Muppets" (just the part with them backstage and Kermit's dull "yay"), and Cookie Monster in rehab (the part with him in the room with the doctors). Even though the rehab part was funny, they got Cookie Monster a bit wrong, having perfect eyes and talking with proper grammar. If it were the REAL Cookie Monster, it's go like...
Doctor: (with a plate of cookies) What are these?
Cookie: Me no know.
Doctor: Whaddaya MEAN you don't know?
Cookie: Me no know how they got there!
Doctor: Well, I think you DO know.
Cookie: No, janitor guy was here making beds... he put them... me was in potty. (gobbles up the cookies) AHHHM-num-num-num-num... (the doctors hold him down) AAH! AAH! You guys Nazis! You freaking Nazis!
Doctor: (gives Cookie Monster a tranquilizer shot) Ssh-ssh-ssh...