If you aren't familiar with the TV show 'Friends', all I have to say is you've got to watch it. Even though it first aired in the 90's and ran through the early 2000's, the show is still laugh out loud funny and contains many creative and unique portrayals of humor. Joey Tribbiani, one of the main characters, is the outlet for a large portion of the funniest moments on the show. He often interprets things a different way than most people do, and this leads to misunderstandings. A good video clip to demonstrate this would be when Monica and Chandler, a married couple (and two of the show's other main characters), are trying to adopt a baby and Joey volunteers to write them a letter of recommendation.
This scene is probably one of the funniest moments from the show, and the only way it could be funny is with our understanding of language. Joey was correct in finding synonyms that mean the same as the original words, however the final letter does not make sense, and that's what makes it funny. The words he chooses don't fit into the given context because the letter is supposed to sound from the heart, and instead it sounds very formal and scientific. The denotation might be very similar, but the connotation of the words is different. He signs the letter baby kangaroo Tribbiani, which if taken literally it does make sense because a baby kangaroo is called a joey, and his name is Joey. This emphasizes the fact that when we are trying to communicate effectively, we must use words that fit into the given context otherwise it will leave the listener lost and confused. Joey might know what he means by "baby kangaroo" but the reader will probably have no idea he means Joey. There is a good article on Dailywritingtips.com that goes more into detail about the problems with using a thesaurus. Just because two words might be slightly similar, using them in different contexts can lead to miscommunication, which often can be humorous.