Boo! No, not that kind of ghost. We're talking about the verb form, when someone you've been dating stops returning your texts and calls. It's most common in the first few months of a relationship, but that doesn't make it feel any less shitty. As this video from Bustle explains, we let down our guards when we're in relationships (it's a central part of attachment theory), so when someone completely falls off the map, it can leave us filled with an inner monologue of self-doubt. It doesn't help that as humans, we're wired to seek out explanations for everything.