I imagine most of us have heard how 'No problem' can be perceived as rude. The reasoning being that saying it implies that the person was bothering you and you generously gave them your time. And true as this may be in some cases, it makes the phrase a prickly ground in customer service. Whereas many users of the phrase may think it indicates 'this wasn't an undue difficulty for me, so I was happy to help' others may feel the above or that you're belittling their needs.
'No problem' is mostly used by younger (I think sub-50 at this point; it's pretty broadly applied) generations while the older still stand by 'You're welcome.' It's a slang thing and pretty broadly done in English-speaking countries (not all, I'm sure, but here, Canada, the UK...)
The other issue, however, with 'you're welcome' is that a lot of people (myself included) can feel some anxiety around using it. It's not that it sounds stiff (though it does), but it feels like it takes away from the person you're helping and puts some power back on you. That implication of 'ah, yes, you're so fortunate that I was benevolent enough to share my time.'
Yet... we should think about ourselves that way. This shift to a service culture we've had in the past fifty years (more fast food, more stores, then call centers and....) seems to have built so many of us into this mindset of 'I must serve' as opposed to 'I am providing a service.'
They're two wildly different concepts. Something about being polite and respectful lies in there, but there's also the simple fact that instead of people viewing customer service roles as someone they pay to provide a service for them, they view customer service roles as someone who is fortunate enough to be the recipient of their money and thus should earn it.
Again, subtle but important differences and they fold into self-esteem at a level that's difficult to comprehend.
tl;dr I'm going to start using 'You're welcome' more than 'No problem' because I'm worth it.
