Explain · Like I'm five version
Opportunity cost in terms of a Tesco meal deal
Choosing something to buy is like picking items for a Tesco meal deal because you can only fit so much into your little plastic bag.
When you go to the shop, you have one main, one snack, and one drink. If you pick the fancy chicken sandwich for your main, you have spent your choice. This means you cannot have the egg and cress one instead. Every time you pick one thing, you are saying a quiet goodbye to the other things you could have had. You only have space for three items, so choosing the crisps means you have to leave the chocolate bar on the shelf.
This is what grown ups call opportunity cost. It is just the sad feeling of missing out on the things you did not pick. If you choose to spend your afternoon playing with toy cars, you cannot spend that same time building with bricks. You can only do one thing at a time, so you have to decide what matters most to you right now.
It is a bit like choosing a drink. If you pick the apple juice, you cannot have the orange juice. You have to be happy with your apple juice, because that was your choice. Thinking about what you gave up is just part of picking what you really want.
Where the analogy breaks downA meal deal has a set price but opportunity cost does not have a label you can see.