Why Do We Buy Stuff?

Here's an exercise I used to do with my sophomores: for one day, list all the products you use in your normal routine. Once you've done that, consider how many of them you really need.
I mean REALLY need.
Many, many of the things we routinely buy and use are things that advertisers have created a "need" for. Some are harmless but useless. Others might not be good for us. We use them anyway, because we've been "taught" through advertising that we must or something bad will happen: people won't like us or we'll turn into ogres.
Some questions to consider: how many different kinds of soap do you have in your home? Shampoo, laundry detergent, hand soap, body wash, floor cleaner, et cetera, et cetera, et cetera? Do you know that some research shows that soapy water doesn't clean your clothes any better than plain water? And soap is, after all, soap. Hmmm.
How about beauty products? We so want to improve ourselves that we buy all sorts of things that our brain KNOWS will not help. Our hearts hope for miracles, nonetheless.
What's the point? Not sure I have one. We like shopping for and trying products. We're used to having them, and they give us the feeling that we're doing something to combat old age or dirt or social ostracism.
It's just when you stop and think about it, we're being had, every day, by clever advertisers who make us want to buy, even feel compelled to buy. And that sometimes irritates me.