Help me understand sac decks

Why do people choose this playstyle? What does it specifically counter? It all seems extremely unfun for the whole table, especially in casual play.

I've only played against Sephiroth and Tinybones, but I hear from others that there are worse commanders that force players to sacrifice permanents?

What gaping emotional pit compels these people to choose the sac playstyle? /j (sorry for my english its my secon language)