Positivity psychology states that material pleasures don't bring deep or lasting happiness, but I have to disagree, at least a little. 

Yesterday, I enjoyed a nice, long, and warm shower - the best I've ever had in my life!  It made me feel relaxed and content, and the contentment has lasted till today.  My limbs and muscles feel relaxed.

And it is not limited to showers - a deep, restful sleep or eating a good meal when one is really hungry lead to the same good feeling.

I know there is much more to happiness - meaningful relationships, dignity and self-worth, social acceptance, intellectual satisfaction, spirituality, etc.

But, surely happiness is partly chemical and psychophysical.