I was watching a video from two years ago about different social norms and this showed up. Found someone questioning the same eight years ago on reddit (when it seemed less normalized). It feels so weird not being aware of this shift, even as a foreigner.
We’re using “problem” to mean “imposition”, not “difficulty”/“error”.
“I had no problem with having to do this for you”, not “I encountered no problems while doing this”.
‘No problem’ is me telling you that I was happy to do the service for you, such that it wasn’t an imposition to do. When I do something for a person I like, I have ‘no problem’ expending the effort to do it.
If I have to do the same for someone I don’t like, I will have a problem with having to do it, but since it’s my job I will not begrudge them whatever it is: they are welcome to it, since it’s my job to provide it. But I don’t have to be happy about it.
‘Sure thing’/ ‘ya no worries’/ ‘ya of course’, etc are neutral phrases.
Bear in mind though that tone and body language are ultimately what you should be cuing on. When I deliver an unhappy “you’re welcome”, it will be deadpan, and I won’t be smiling.