An earlier edition of the PFS guide included the guiding statement
Play, play, play. and intended it to be a reminder for why we have all come together. So, at my table:
Play - Have fun. Make new friends. Enjoy yourself. But also let yourself enjoy others at the table.
play - This is a game, and like most games, it has rules. Try to know and follow the rules but also its fine to ask questions. Since the goal is to have fun it only lessens your fun if you cheat, so don't cheat. Rules are one of the ways we balance things so everyone has a good time.
play - This is a chance to be heroic. Do so. Take risks. Be creative. Be larger than life. Try new things. Come away with a story you want to tell your friends about.