15 Best How I Met Your Mother Episodes
4. The Time Travellers (Season 8, Episode 20)
"Look around, Ted. You're all alone."
The Time Travelers is one of the show's most emotional entries. It serves as an almost-bottle episode, in which Ted and Barney sit in their usual booth and converse with past and future versions about themselves. Barney wants Ted to go to Robots vs Wrestlers, but Ted isn't sure until their future selves put them on the right path.
At first, things seem pretty normal, with Barney trying to drag Ted out for another wacky adventure. Along the way, Marshall and Robin fight over who created the bar's new drink, and at one point Ted spots a woman he knew years ago but never asked out.
It is here that cracks begin to form, as he realises there's no point asking her out because his relationships all end the same way. Then, much to Ted's surprise, Barney reveals that everything that's been happening that night has been his imagination, and that he's alone, the odd one out of the group.
The Time Travelers is a perfect encapsulation of the show - Ted's sure fate will bring him to The One in time, but he's lost hope as his friends are all moving on with their own lives.
On a plus note, it ends with Ted and Barney's rendition of Billy Joel's "Longest Time", so it's not all sad.