Not a singles line issue, but I had a woman with 2 young kids, waiting for a quad chair, ask if the father and son, behind us, could jump in front of us in line "so her kids could ride with their friend". I'm not the smartest cat out there, but I can manage with simple math... 3+2 does not equal 4. I simply said "well, if you want to ride together, just let US go in front of YOU, that way your group will be united. Everyone wins." She looked at me like I had two heads. Absolutely no understanding of a solution that wasn't 'her group taking two chairs in front of me'.
People are inherently selfish and often rather stupid. This leads to friction, it's unfortunate, but in the end we are all just sliding on snow, which is also kind if stupid... so just have fun and don't let others bother you.