There is a not negligible chance you would have died as a child, or even an adult, from any number of diseases that used to be far more widespread. Certainly it's likely at least one person you know would have.

Modern sanitary practices have saved literally millions of people. Not hand washing alone perhaps, but it is a significant factor.

Humans now live in populations of millions of other people that are constantly in close contact with each other, and people travel more and faster than ever before all across the globe. Be thankful we haven't had more plagues.