Slang definitely has its place. Beside the words being fun, they say a lot about groups of people. For example, you can usually tell if a person is not from where you live by certain words. My friends from New York used slang I never heard in South Florida. But I liked it!
Here is an example that is really cute!
Where I come from, if you're in the back seat of a car and the passenger in the front seat has the car window rolled down and a lot of wind is hitting you in the face, we would say: “Hey! Take me off the beach!” That means “roll up the car window”.
My late husband was from The Bahamas. To ask the passenger to roll up the car window, he would say: “Hey! Put yo lil man drawers on!”
The first time I heard him say that, I was like: WHAT??
Slang adds flavor to a conversation. It's interesting to know that some of the words go back hundreds of years. Even if you don't use slang, the study of how the words came to be is interesting.