Why does every decision made have to involve trade offs?

The prevalence of trade-offs is a result of the complexity of the world in which we live. Simple situations do not involve trade-offs. You are wandering through the savanna, you are hungry, you come upon a fruit tree bearing delicious, ripe fruit; you eat one. No trade off is involved.

But if you are a busy city dweller, trying to decide whether you should buy a new television set, that is more complicated. There are thousands of other things you could do with the money.