Most people a few years ago though that collisions didn't happen.
Suddenly we're starting to get lots of collisions. There's probably one about every ten seconds.
It you waited ten million times the age of the universe, only then would you have a 50-50 chance of a collision.
They are the most violent energetic events in the universe. Some release a thousand times as much energy in a few seconds as the sun would in its lifetime.
They have no business being there. There's no other way to make them, other than to collide stars.