Sesame Street has always been an amazing program. It's the one kid's show that outclasses all others, and for over 45 years, the educational program has defined millions of childhoods. It works because it's always made learning fun: between the different sketches and numerous guest stars, Sesame Street was never boring, and that's how it managed to keep kids engaged.

Nowadays, the show is known for bringing the likes of Ian McKellen and Macklemore in, but huge celebrity appearances have always been a part of the series' DNA. It was yet another way that kids could feel connected to what was happening on screen...however, after more than four decades worth of guests, there were bound to be some misfires. Considering what they were famous for (or became famous for), perhaps some of Sesame Street's guest stars should have been left at the gate...

Richard Pryor

He was one of the greatest stand-up comedians who ever lived, but Richard Pryor's material is far from anything that would even be seen on television, much less Sesame Street. It's understandable that the show's producers would want Pryor following his goofy appearance in Superman III, but Pryor first appeared on the Street in 1976 - seven years before Superman III's release. Sure, his segment is clean and isn't offensive in the least bit, but for such a raunchy comedian to appear on a children's show is still a bit of an enigma.

Katy Perry

Granted, Katy Perry's music isn't exactly for kids, but the music video she shot for Sesame Street was entirely harmless, right? It's not the greatest thing in the world, but there's no way it could do any damage.

Apparently, not everyone felt the same way: after the video debuted online, hundreds of outraged parents demanded that the segment be pulled due to Perry's revealing outfit. The producers complied, though it's still difficult to understand why...

John Leguizamo

Now, there's really nothing wrong with any of Leguizamo's past work (he was Luigi, after all), nor is there anything wrong with what he's wearing. He's actually a pretty great choice for the show - except that the skit he appeared on was one of the most bizarre things to ever appear on television. Sure, there were probably some kids laughing at the suit covered in vegetables, but would anyone ever want Leguizamo singing ever again? Probably not.

The fact that he called Elmo a 'playa' doesn't really help matters.

Larry King

As a news anchor and journalist, Larry King is an American icon wrapped in suspenders. He's defined his career with a single, hard-hitting show on politics and culture, and will go down in history as one of the greats. While that's all well and good, it doesn't really translate to a children's show...at all. Instead, the producers of Sesame Street had Larry King interviewing the letter 'W' in a segment that surely left a lot of kids confused. How many four-year-olds are watching Larry King Live?

Props for the "Who's On First" references, though.

Cheech Marin

Cheech Marin falls into the same category that Richard Pryor does: aside from Sesame Street, none of these comedians' other material is fit for kids. Sure, Cheech went on to star in kids' movies, but that wasn't until years after his Sesame Street appearance. At this point, Cheech was known for one thing, and one thing only...which is probably why he appears in a puff of smoke. We're sure that joke flew high over every child's head.

There you have it: proof that Sesame Street hasn't always been on-point when it comes to its guest stars. Of course, after nearly half a century of being one of the greatest and most influential children's shows on the planet, perhaps a few misfires aren't the worst thing in the world...