The Delta variant is sufficiently contagious that all of us can expect to be exposed multiple times in our lives. Just like what typically happens with the other endemic coronaviruses.

https://www.businessinsider.com/delta-variant-made-herd-immu...

Only a subset of those infected will experience clinically significant symptoms. Probably more than 3 of your acquaintances have had it but didn't even know it, maybe just felt a little tired for a few days.