Lots of stims are not too bad. It's meth that really fucks people up.
It's doing the most damage in small town USA. If you're in a town of 1000, and there are 50 meth heads, it is very noticeable. In big cities you can just totally avoid it easily though.
Or if you live out in the country, and there are some meth heads living down the street, it can ruin a neighborhood quick.