Bar Conversation With Random People

After being introduced to two people that are engaged:
NDC: [To girl] Congratulations; I’m sure you’ll be happy forever.
Girl: Thanks.
NDC: [To guy] Run. The. Fuck. Away. Now. I’m dead serious; get the fuck out while you still can. You’re slowly walking down the long road to unhappiness and self hatred. You need to get out of the state as soon as possible.
Guy: [Laughs]
NDC: [To girl] I’m just fucking around. I’m sure you’ll both be happy and you both love each other.
Girl: [Laughs] Well thank you.
NDC: [To guy] I’m not fucking around at all. This is the end of your life. Really? One vagina for the rest of your life? How does that sound? That sounds like shit. What the fuck is wrong with you? Are you fucking retarded? Were you dropped on your head as a child? Did you recently suffer severe brain damage? What in the name of christ makes you think that this will end any way other than badly?
Guy: [Laughs]
NDC: [To girl] Again, I’m just kidding. I’m just bitter.
Girl: [Laughs] It’s ok.
NDC: [To guy] You may as well just cut your cock off right now because you’re not going to need it for the rest of your life. And while you’re at it, go ahead and hang those balls up too. Once the ring's on their finger it’s all over. Once you’re married all of a sudden it’s “wrong” and “immoral” to fuck hookers, get drunk every day, and stay up for two weeks straight doing rock and meth. Run away while you still have dignity and self respect. I’m warning you.
Guy: [Laughs]
NDC: [To girl] I’m joking. I was actually engaged once. [Turns to guy] Then one day I accidentally sobered up and realized that I needed to get the fuck away as soon as possible. For your sake, I hope you do the same.

Discussion question: Why the fuck do people talk to me?