By and large, television shows teach you nothing; they’re purely for entertainment, nothing more. In other words, after watching an episode of 24, you shouldn’t expect to be able to hack the government firewall, decrypt protected files and/or stop a terrorist plot in a day. I don’t care how well Chloe and Jack do it on television; it simply cannot be done.

Still, occasionally, you can learn something from some of the less… extreme shows, like How I Met Your Mother.

Here, Barney Stintson, played by Neil Patrick Harris, explains the four reasons an ex would want to have lunch with you. When you think about it, there really are only four reasons, and these are it:

1. They Want to Get Back Together: This is the most obvious one. They either want to win your love back or enjoy one more lust-filled rendezvous.
2. They Want to Kill You: OK, this one is rare, but still plausible… if you date insane asylum inmates.
3. They Actually Want To Give Your Stuff Back: Remember those boxers you left at their house? Yeah, they don’t want them anymore.
4. To Rub In Your Face How Well They’re Doing: Expect to hear how they won the lottery, they are getting married and/or they’re moving to Hawaii.

Yeah, exes suck.