How I Met Your Mother: 10 Biggest Unanswered Questions
9. What Happened To Robin's Other Friends?
Once Robin starts to get closer with the gang, she begins to make little quips about how she has no friends and doesn't know anyone in New York. But, according to the very first episode, this isn't entirely true, as she's seen in MacLaren's Pub with a recently dumped friend.
This same friend is seen again in the second season, and in season six Robin reconciles with her old childhood friend and fellow pop star Jessica Glitter, who's subsequently never seen or even mentioned again.
Narratively, it's easy to see why this happened, as the writers needed to keep Robin together with the gang, but the fact that she keeps making a point of how friendless she is only emphasises the fact that she actually has quite a few other friends throughout the show, they just all disappear without warning or explanation.