The last time I was on the LIRR was 25 years ago. I was traveling to visit family with my then 3 year old to save them the 2-3 hour horror of picking us up at the airport. We were on an fairly empty early afternoon train from Jamaica at the back of the car.
We were riding along when my daughter says in her unmodulated child voice, “Mommy, why does everybody look so angry?” Slowly people looked up, looked around and started smiling at her, and each other. It was kind of amazing.
But most New Yorkers are very decent. They only appear rude because pretty much anybody approaching them is a panhandler or scamster. My recommendation for tourists looking for directions and such is to approach a NYPD officer as they will definitely help you out.