To me, it's more precisely about someone popular, or well-respected, that everybody think of as clever, deep, etc (everyone mistakes the things you say...), but is actually pretty shallow and is repeating easy truths to make themselves seem deep, which would refer to the "dog new tricks". Like something you teach to a dog to amuse yourself, that person is shining in society by metaphorically sitting, rolling over, catching the ball... The "you make me feel so worthless" part would be about how she feels belittled by this person's pretending to be so much better than her. It actually might be someone that she appreciated before and became that way to make themselves popular in society (I would have never pegged you...), so it stings even more.
To me, it's more precisely about someone popular, or well-respected, that everybody think of as clever, deep, etc (everyone mistakes the things you say...), but is actually pretty shallow and is repeating easy truths to make themselves seem deep, which would refer to the "dog new tricks". Like something you teach to a dog to amuse yourself, that person is shining in society by metaphorically sitting, rolling over, catching the ball... The "you make me feel so worthless" part would be about how she feels belittled by this person's pretending to be so much better than her. It actually might be someone that she appreciated before and became that way to make themselves popular in society (I would have never pegged you...), so it stings even more.