Break-Ups Should We Do This Civil or Should We Make This Messy

When you've been in a "how long is too long" relationship and its time to move on should the break up be messy or civil? A lot of people would argue that if the relationship is over it should be civil.  Some people would make it messy and drawn out because they still have feelings for their ex.  

Relationships shouldn't be messy if they are over.  There is no need to bust a tire and/or window?

Can you still be friends?

What about when they move on, can you deal with that?