What would be the most hurtful/painful way someone could break up with you ?

My neighbor went to work last Friday and while she was at work,her live in boyfriend moved out.
That morning he acted all nice and sweet, gave her no notice at all,didn’t even bother to leave her a note !
*I briefly talked to him while he was loading up his furniture,he smiled and said it was actually from a rent-to-own place and he was just upgrading.