A somewhat less monetized way of looking at opportunity cost is to say that money, whether it is saved, spent, invested or squandered, will only tend to finance such opportunities as we value.

When I have a broken leg, I obviously want the opportunity to have it set by a doctor. But no matter how much money i have, I will never take the opportunity to build a mansion in a swamp.

What really matters to me in terms of "opportunity costs" are lost opportunities to accomplish what I value most. Once my basic needs for food and shelter and general health are met, I value backpacking very highly. More than almost any other opportunties, regadless of the amount of money they would cost.

So long as I have the money to meet my basic needs, year in and year out, then anything beyond that which I spend on backpacking consists of gleefully, joyfully, enjoying the opportunity to hike, and my money is achieving its highest potential, regardless of whether I could have bought stocks and earned myself lots more money to spend. What else could I spend it on that's half as enjoyable as hiking?