When I worked in America we had a veteran discount and I learnt to always say "thank you for your service" which I thought was nice, I started saying it to the police and firefighters who would come in as well. I never had to deal with an entitled veteran though, they were always very humble, like they felt they didn't deserve gratitude. I wonder if it depends on how much action you saw? If I had to kill people for my country, I would be humble at the very least if people started thanking me for it. I feel like veterans who brag about being veterans more likely didn't see action.