I usually throw this at them when they are feeling iffy or saying they're busy (signs of disinterest, I know). But I'm not going to incessantly text and chase them so I'll just tell them to text me when they're free or whatever. Aan then lo and behold, I never hear from them again. Bonus points if I see a Facebook post or whatever some time later of them with some new guy.
I know that two people aren't always going to match up but damn. It seems like so many girls don't want to put in even half an effort and I certainly don't want go have to carry someone like a dead fish through a relationship. O don't want to spend time with someone who doesn't want to spend time with me.