My dad played at open mics and some of the same guys would show up at different open mic nights. Some of them helped each get gigs or record songs and my dad became really good friends with one of them. They’ve been friends for about 25 years now.
Also my parents became friends with a lot of my friends’ parents. They’d see each other at different school functions and eventually started hanging out. Now they see other more than I see my friends.

I rented out my spare room. She moved in. I’m a best man at her wedding this july

I was stood at a bar and told the barmaid that a homeless man had told a friend of mine that a shot of cointreau makes even the roughest cider drinkable. The woman next to me said “I have to try this thing” and promptedly ordered one. Besties for ten years now.

I actually met one of my closest friends on a dating site. We tried a few dates and it wasn’t clicking but we got on so great that we didn’t wanna stop talking to each other. He’s my go to cinema and boozing pal now!

I heard a New Zealand accent in a small town in the UK when my husband and I were out for dinner. Obviously introduced myself. Best of friends even now that we live half a world away..

I went to the animal shelter and there he was. After a couple of dates he moved in with me. My best friend is my dog.

Image Credit: Lifewire

I’ll answer for my husband seeing that this question applies to him. He joined an online racing community that would have weekly races and through it met a guy who he got on really well with because they had so many common interests. For a while they lived in the same city so they actually met in person a couple of times, but then his friend moved. Now my husband would never admit out loud that this guy is his best friend (he thinks that’s a girl thing) but they totally have a bromance. They message each other several times throughout the day, usually about F1, other sport, guitars, politics or some random thing. It makes me happy because he’s never had a best friend as an adult.

We were both reluctantly attending a birthday party we didn’t want to be at – me because my roommate was the birthday girl and him because he’d met her at a bar the week before and she’d insisted he come. To be fair, it was on a boat, which is why we each agreed to come against our better judgment. The birthday girl got rip-roaring drunk, sang karaoke when nobody else was participating, and generally made an ass of herself. He and I were both wearing superhero t-shirts and got into a heated discussion about Captain America versus Iron Man. Then two weeks later, he turned out to have been hired by my company, and now we see each other pretty much all the time. We still agree to disagree about the rankings of superheroes.