How I Met Your Mother: 10 Worst Breakups
4. Barney And Nora
While Shannon was responsible for turning Barney into the man he is, Nora was the first to begin his journey back to the man that was.
Nora first appears in season six as a co-worker of Robin's; shown to be smart, witty, and beautiful. More than that, her character is the first serious girlfriend that Barney has after his doomed initial outing with Robin. Nora aspires for everything that Barney is fearful of: commitment, children, and her one true everlasting love. Despite this, Barney is shown to fall for Nora, and the audience is brought along on a journey of growth for the character that hadn't been seen up to that point.
Unfortunately, old habits die hard, and Nora's trust is broken when Barney cheats on her with Robin after a drunken one night stand. Barney and Robin are both in relationships at this point, and while they are wracked with guilt over what they've done, they also believe it happened for a reason, that they're perhaps meant to give what they had another go.
The casualty of this epiphany is Nora's heart. Barney confesses his infidelity, and in a powerfully poignant moment, she tells him she can forgive him if he tells her it meant nothing. Alas, Barney cannot, and a relationship that provided so much growth and love is ended just like that. Which, it turns out, is actually for nothing...