A betrayal machine: people are put together as betrayal machines. There's some component which causes you to trust them. And then there's a payload of betrayal that gets you when your defenses are down.
Your defenses can be lowered by good aspects of other people as well as their defense-lowering tactics. People can prove trustworthy on lower levels of the hierarchy of betrayal only to betray on higher ones.
The payload of betrayal might be a hatred only known to the betrayer, or perhaps some tendency unknown to them. To take a not-so-emotional example, if your arm spasms and jerks out, you could strike someone by mistake. This ongoing spasm goes with you wherever you go, as though you were possessed by a demon. Often enough, the spasming-arm is an emotion. If you are a person with a "spasming arm", on some level you're always aware of it during or immediately after the motion, but on another level, you might not be, for having become so used to its random or irregular re-occurrence.
[See also Inherent Danger of Trustworthiness.]