In the cannabis plant we have many organic molecules - cannabinoids (you've heard of THC and CBD among others) and an array of aromatic molecules which we can simply refer to as terpenes.
While we use cannabinoids for certain uses, terpenes in general can cause certain effects. For instance, the terpene Borneol may help with pain relief. If you have anxiety you may want to avoid certain terpenes like Myrcene, and go towards Caryophyllene.
Do you pay attention to what terpenes are in your cannabis? Which one do you look for?