People who refuse to vaccinate themselves and their children not only put their own families at risk, but other families as well. But despite contributing to the spread of dangerous diseases, most "anti-vaxxers" are driven not by a desire to make people sick, but by ignorance, misinformation, and fear. And oftentimes, the right combination of circumstances and education can help them change their minds.
1.) From Xincandescent:
I was a teenager and used to believe that if I got sick, my immune system would handle it and make me stronger. Like most youth, I believed I was invulnerable. I figured, thousands of years of ancestors had survived without vaccines, and so could I.
It was years before I realised that before vaccines, people didn't just "heal the viruses away" - most of them died or were crippled by illness their whole lives.
EDIT: Surprisingly, I was a well educated kid. I loved human biology, and aced the test on the immune response. I still remember terms like macrophages and leucocytes. I knew how vaccines worked, yet despite this I had this flawed logic that if I got a full-strength illness, I'd develop a full-strength response. In my quest to grow stronger and find my limits, I would have dipped myself in every sickness known to man, giving myself a week or two to heal, until eventually I was immune to everything. God I was dumb.