I know most people might find it funny the reason why i choose this title, maybe thinking why can't just i title it "trust nobody".
I just think the word sly have a greater meaning than dishonesty. Sly means you are been pretended to be loved, someone that got your back messed you up. A sly is artfully cunning; secretly mischievous; wily. The artfully means skilled, prepared right from the start to mess you up later.
Everybody is a potential sly, simplified ;trust no one, not even your blood relations, because everybody or anybody are potential sly. Some sly or betray you simply because of circumstances, or they can't please you to displease themselves, its might even be solely because of greed, but anyways have it in mind you could be slyed anytime, anyday, by some you know or you don't, by some you aren't close and the ones you hold dear to you. You having it in mind makes it harder for people to sly you, and if it happens, it makes it easier to get over them.