The disappoint from the show.

I think Ted returning to Robin was a big disappoint cause it means that he had feelings for her even the mother was alive.
i think you should never hangout with your exs as it will keep the spark lingering especially if you were best friends.
this would definitely affect your relationship with your current girlfriend.
and you would not able to give your 100% for your relationship.
its just my point of view as nineteen year old.
thing can be different when you grow emotional maturity in future.
NO OFFENSE