Why are they popular? Why are they addictive? Because you are evolved to love them.

Pringles contain (In descending order of significance in the composition):

Dehydrated potatoes
Basically, starch.
Vegetable Oil
Corn flour
More starch. The kind that easily breaks down into sugar.
Contains many things, but includes sugar and flavour enhancers Monosodium Glutamate and possibly disodium guanylate depending on the flavour.
Gluten-free Wheat starch
Sugary goodness.
Another sugar.

So why are you Mr. Pringles' bitch? Because you are evolved to want foods that give you energy. Now. Don't wait - it might be gone later! All of the ingredients above are prime sources of energy. Fat is pretty much the best taste ever for humans, and sugar is pretty top too. You also need those more complex carbohydrates, the starches, for longer-term energy. Salt is nature's flavour enhancer, and a vital component in your diet. Hard to come by when you don't live near the sea. Those of you who have a "no protein with carbohydrate" diet can rest assured that with less than 0.3% protein, Pringles won't ruin your child's stuntedness!

With pringles giving you all the kinds of energy-bearing food you need, your instincts are telling you that you want them, as when winter sets in, who can tell where the next Big Mac is going to come from?