15 Saddest How I Met Your Mother Episodes

15. The End Of The Aisle (Season 9, Episode 20)

After twenty-one episodes, set over one weekend, Barney and Robin were finally married at the Farhampton Inn. But even in the final moments leading to their union, the pair hit some major bumps. Robin panics about the idea of marrying Barney, sure that the fact she never found her long-lost locket is a sign they won't work. Barney, meanwhile, struggles to write his wedding vows.

Watching Robin panic is sad enough, though becomes kind of heartwarming when she (literally) runs into the Mother, who calms her down, but the true kicker of the episode comes in from a side-plot about Marshall and Lily. As Robin and Barney freak out, the show's perfect couple duck out and renew their own vows, each giving sweet and teary-eyed speeches about how much they love each other.

Best of all, Barney sees their vow renewal and it gives him the push he needs to confront Robin about his panic. It's sappy and moving in all the right ways, and is bound to make you tear up.