You'll have fewer pesticide spills when you are alert. Count to 10. When your customers seem unreasonable, stop for a minute before you respond. Keep your cool and you'll have fewer accidents. Keep your training up to date.
Less stress means fewer mistakes.
Communicate with your boss. Talk about what is happening out in the field. Communicate with your family. Summer is always a rough time for pesticide applicators and their families. They are your support system, so don't treat them as if they were the problem.