When you take actions based on your own well-being, you are making a personal calculation - how much risk am I willing to take on. You are then making choices based on your personal risk threshold.
The problem with this is that you aren't taking into account the vast externalities as a result of your decisions. Your actions don't only affect you, they affect the health of the public.
I've found that flipping the script from: I don't want to catch Covid-19, to: I may already have Covid-19 and I don't want to spread it to others, helps you understand the externalities of each action you take.
For example, personally, you may feel like you are comfortable with the risk of going to the grocery store to stock up. You've decided that the risk for your personal health is lower than the benefit of additional food from the grocery store. Your risk is something along the lines of:
My Risk = [(average number of people that will also be there) * (average level of contact or exposure to those individuals) * (average likelihood that each of those individual has Covid-19)] - (how healthy I think I am) - (how good I think I am at avoiding contact) - (how good I think I am at sanitizing/chemically mitigating my exposure)
Note that most of those things are in your control. The ones that aren't you probably have some sort of educated guess as to what they may be.
Let's flip the script on that. What if you had Covid-19, and you were trying to understand the risk you were imposing on others. That might look something like:
Risk to Others = [(average number of people that will also be there) * (average level of contact or exposure to those individuals)] - (how healthy you think they are) - (how good you think they are at avoiding contact) - (how good you think they are at sanitizing/chemically mitigating my exposure)
Now, all of a sudden there are a ton of variables out of your control. You have no idea if anyone has pre-existing conditions. You have no idea how seriously other people are taking this. There's potential that you're imposing a tremendous amount of risk on those around you -- you have no control over their actions, only your own.
This exercise is about expanding your thinking beyond yourself. Understanding that your actions don't just have consequences for you, but for everyone around you. It's a tool to help you visual and re-calculate the risks you may be taking.