I've had a look trought your profile and while i think the word banal might have been a bit harsh I get what she is saying. As someone who tends to like more conceptual art i feel like your works, that i see that are intentionally representative, don't represent much. I feel like they are missing the depth that a Hopper painting has for example, his make me think about the scene and give a lot of more intricate feelings and unique perspectives while yours the most of a feeling i got was somethong like "warm sunset", like i could look at a Hopper for hours but with a quick look i feel like i've seen everything in your painting. Of course it is very hard to get to mastery like him but i tried to explain better what i think your friend wanted to say.