I encourage PCs to take Judas, In Debt, Lost Loved One, Prejudice, and other interesting negative qualities. If the PCs take them, that is what they want to happen in the game. It is really easy to pick on a player who buys a shiny new gun—but denies to spend the money on their sever NovaCoke addiction; what is the PC going to do there? go into debt with the local dealer, or do a job for 'free' with the local street gang or organized crime group?
When players make contacts with 4-6 Loyalty, have them show up and want to hang out. What is the PC going to do? blow off his friend to continue legwork (the PC knows he has not seen his buddy in a while) or go out for a night of drinking and be hung over for the run?
Exploiting what the players put on their character sheets is the easiest thing to do, especially since it costs Karma to get rid of Negative Qualities. Often times, the sheet will expand into the rest of the game and make extra complications: "Oh, you insulted a group of dwarves and had to leave the casino you needed information from. Next week the metahuman rights group shows up to try to fix you of your ways. You close your door in there faces? Cool. They hire a Horizon spokes team to change your mind: get ready for non-stop Horizon education ads spamming your inbox for the next week."