Very good explanation, dear friend @angeluxx. It is very true when you say that opportunity cost does not only apply to the financial world, but can also be applied to many areas of life.

Here's a personal example.
I used to work as a healthcare professional in my country, and unfortunately I had to quit because my salary wasn't even enough to pay for two days of transportation to work. In other words, I was no longer working to earn a benefit, but rather it was costing me to get to my workplace because I had to find money elsewhere to pay for my transportation.

I had to weigh up whether to continue working or resign, and although I loved my job, I had to resign because I was no longer working to get paid, but was paying to work.

The cost was higher than the opportunity.