Well, our brains are wired to seek out novel and pleasurable experiences.
Do you consume alcohol or caffeine? If so, it's probably because they make you feel good; a lot of people smoke weed or take LSD or MDMA for the same reason.
For a lot of people battling mental health problems and/or horrible life circumstances, drugs also offer an escape from feeling like shit all the time.
I dont consume alcohol or anything that has caffeine.
The only liquids I drink are either Water or Milk.
I dont drink coffee, tea, juices, sodas, alcohol, etc.
There's plenty of other pleasurable things to engage with to ease one's mind off of stuff than consuming drugs or consuming unhealthy substances.