A paint sprayer from a hardware store can cause paint to spray off of your brush. The pressure from the trigger is too high for the paint to stay on the bristles. This can cause a lot of waste and mess in your work area. Some people have said that it's because of how you hold the brush, but others say it's because of how you hold the trigger. It's not just about holding your brush differently, but also about what kind of paint you're using and if there are any contaminants in it.