You really can't tell if you don't know the person. I have a bright, weird personality and ADHD and work at a dispensary. People often think I'm high, assume that it's part of my vibe, but I'm strictly no THC during the day. Meanwhile, one of my most down to earth, serious, no nonsense coworkers does dabs before work and on all her breaks. Nobody thinks she is high all the time, but she's often the most THC filled person in the building.