it is relatable

How I Met Your Mother works because it's so relatable.

In one episode,

Robin : Ted, am I the biggest idiot in the world?

Ted : Think about all of us, 5 years ago, when we first met you.

Marshall and Lily were just boyfriend and girlfriend. Now they're married and thinking about kids.

And Barney.. Barney was never going to commit to anyone, ever. And last year, he fell in love.

And me, I was chasing a girl I was convinced was the one, and now she's one of my closest friends.

And you, 5 years ago, you would never choose love over your career. And today you did.

Robin : Looks like I'm getting dumber.

Ted : No, just more courageous.