You can't buy, inject, drink, swallow nor anything else that will give you happiness. Even winning the lottery will only give you fleeting happiness even if it gets you out of a financial predicament and you buy all your desired clothes and cars etc.
You can win your dream super car and next day crash it with devastating injuries - where did your happiness go? Happiness is something that is an inherent part of who you are, if you choose to outsource it such as go to a lecture or buy a book hoping that someone else will give you a key or pointers to where happiness can be found you will die waiting as it is already within.
It is your choice to be happy, so if you place material or conditional effects upon being happy then that's what your life will consist of. It's true you can meet your heart's desire and become deliriously happy, but the continuation of that is a choice not something that by itself will be upheld.
Enjoying life come what may is the essence to being happy, it's something about you, your character that wants to enjoy and wants to embrace happiness and it will show through.
This audio download explores why some people are happy and some are not and that it is really a choice based upon your own self respect.