Saying "No problem" means different things to different people though. In my generation, asking someone for help almost feels like you're being bothersome to that person, and so when someone says "thank you" to us, we want them to know that it was our pleasure to help them - the person asking for help wasn't a bother. It's not being rude, it's just a generational difference. To millennials, it means the same as "you're welcome." Nothing to get upset about.
Saying "No problem" means different things to different people though. In my generation, asking someone for help almost feels like you're being bothersome to that person, and so when someone says "thank you" to us, we want them to know that it was our pleasure to help them - the person asking for help wasn't a bother. It's not being rude, it's just a generational difference. To millennials, it means the same as "you're welcome." Nothing to get upset about.