Diminishing Marginal Utility

The law of Diminishing marginal utility states that for every subsequent unit of goods or service offered, the marginal utility of that good or service decreases.

Aashray was explaining this to me after I asked him to explain me some economics shit so that I am better prepared for my college when economics classes are held.

So basically he means to say that the theory states that the more of something you have, the less of it you want. Marginal utility is something like satisfaction.

Say like the more paani puri you have, every subsequent time you have a pani puri you will want it less.

But I don't think this works - with say something like diamonds or condoms.

He told me economics was a bunch of complicated sidey theories that you didn't really need to know anything about.
So we went back into the realms of science, where I explained to him the bladder capacities of humans, and the definate diminishing marginal utility of public toilets.