Why are most Male workers at Fast food restaurants nicer than the females that work there?

It always seem when I go or my sisters go to a fast food place (McDonald's, El Polo Loco etc.) the guys are always 10x's nicer than the female employees. Like if you ask for a BBQ sauce a female always NEVER FAILS ask for extra money a guy always like "it's cool here you go". The guy last night just said "Don't trip, I got you" and gave us a bunch of stuff. Why are female employees (NOT ALL are like this) but alot are not as generous, nice or giving as the guys?. Guys let everything just roll of their back in a cool serene it don't matter type of way. Has anyone else noticed this?, I've always wondered this cause I've noticed this since forever.