Marijuana gets a lot of credit for making people merry. If you wanna be merry and you use marijuana to that end, you should not give credit for your happiness to the drug. Marijuana, like any psychotropic drug, will shift your perception. That experience could be pleasant. Boring, regular life, could seem more exciting and interesting from the different perspective. The sudden shift in perception that marijuana produces is a good demonstration of how your mind creates your experience. If you give the drug in marijuana full credit for your experience, you may start to worship a false idol.
Your experience is your experience is your experience. Your perception shifts constantly in response to all kinds of chemicals in your internal and external environments. Smelling baking bread is an example of a chemical reaction between you and your environment. If you feel happy when you smell bread, you tend to take full credit for enjoying the experience. You give little credit to the bread. You breathe in deeply and enjoy the scent.
If you are high and you smell fresh baked bread, you may also appreciate the scent of bread, but you may give credit to marijuana for making the bread seem to smell so delicious. Then you may eat the whole loaf.
Experiencing your consciousness is a full time job. Happiness is deeper than merriment. If you wanna be merry, play with experience. If you wanna be happy, experience yourself.