People don't love Just Cause 2 for its story, or its characters. They love it for the fact it's a giant toybox, giving them the vehicles, the environments and the physics to do whatever the hell they want.
Want to tie a jeep to a plane? You can do that. Want to drive a boat off a pier and crash into an exploding motorbike? You can do that.
Want to throw a bus off a cliff and see what happens? You can totally do that.
Just Cause 2 Insane Bus stunt [Reddit]