Most people do not do much regulation of their states, at least not productively or masterfully. (Eating sugar or taking stimulants, drinking alcohol are not masterful strategies!)
But it is so easy to learn to do this just through breathing and you need only know 3 methods to do it.
To be a master of life and of happiness, one must be a master of one's states.
The Core Guide To Mastering Breathing - a short booklet, with a single reference page for what to do.