I don't ever tell someone who is at work to "have a good day." That's ridiculous. They can't have a good day. They're working. Work is ruining their day. Work is not something you do to give yourself a good day. Giving other people a good day is what you're doing when you're working. You're serving. You get paid but if you focus on the money you'll usually feel underpaid. Don't tell someone who's working to have a good day. Just say thank you.