It's good to be concerned for the health of others.
Carol lives in a building where there are many activities organized for the residents, many of whom are elderly like Carol.
Carol wants to have fun by joining an in-person activity.
Carol calls each participant ahead of the activity and asks how they feel.
Carol doesn't care much about other people's health and doesn't ask anyone involved in the activity how they feel.
Carol discovers that one of the potential participants doesn't feel well and encourages her to stay home - and no one in the activity is infected.
One of the participants is actually a bit sick, and soon after discovers she has Covid - Carol and others are infected.