I don't understand why you would ever want to treat someone in a crule way on purpose. To me that's exactly what "Breadcrumbing" someone is!
If this is the first time you're hearing about it, no worries, you're not alone. The definition of Breadcrumbing: "The act of sending out flirtatious, but non-committal text messages (i.e breadcrumbs') to members of the opposite sex in order to lure a sexual partner without expending much effort."
This article in The Daily Mirror goes onto say, "Breadcrumbing perpetrators are essentially giving you false hope that you matter to them in some way, or have been on their mind, yet have no intention of following through with interacting with you in a meaningful way."
In other words, you are just messing with peoples emotions for your own enjoyment. Very sad!