Tips on keeping my cool during lunch and dinner rush?

well I work at arbys 55 hours a week and during the lunch rush from 11 til 2 our store does about 1500.00 an hr. I get flustered easily when our expo people, who are usually the managers, are being short and giving attitudes to us on back line. How do you handle yourself during your lunch rushes? I try not to let minimum wage screw my day up but it usually does because I'm a pr**k when I'm finally off.