It's so important that people at your job don't know everything about you. Even if you like your coworkers and have a solid bond, there are some things you shouldn't tell them. Even if you think they have good intentions, they could use aspects of your personal life against you in the workplace. You never know who's going to tattle to the boss about something utterly unrelated to the job you're doing. This is especially true in restaurant and retail employment situations, where gossip and drama are much more likely to cause somebody's downfall.
One Redditor recently got fired from a BBQ restaurant for the prettiest reason in the world. Her coworker snooped through her phone and found she had several apps designed to help people recover from drug addiction. Instead of the coworker getting in trouble for looking through her things, the woman in recovery got fired for "being a drug addict." That's gotta be illegal, and yet, it happened.