Are you creative?
If you answered "yes," then you already know the gist of what I'm going to say (but please come along for the ride if you like).
If you answered "no," then we'll try a different group of questions:
If you're walking across your living room and there's a coat thrown on the floor, what do you do? (Do you step around it? Do you pick it up and hang it in the closet?)
If you go to the kitchen looking for a snack, how do you proceed? (Do you open cabinet doors and the fridge until you find something that looks appetizing?)
If you're about to smile and say 'hi' to a friend, but notice that they look sad or pensive, what do you do? (Do you change the expression on your face and ask them something to find out more about their mood?)
You probably do all these things, or something similar, right? So... yes, you are creative! (Aha, I knew it!!!)
The reason many people claim they aren't "creative" is because in music, our society has a false definition of creativity. Many people think that creativity is sitting down at the piano and wondering what it would be like to play Mozart-style music with a Brazilian rhythm (as Patrick Moraz did on his groundbreaking The Story Of I recording in 1976).
Yes, that's creative, but it's also rare. And not always necessary, in fact.
Musical creativity is also:
Deciding to analyze the chords to the written piece you're working on.
Practicing slowly in order to play faster later on.
Phrasing the melody to a pop song the way a vocalist might sing it.
Playing the bass line a little more staccato on some notes, without even realizing you're doing it.
Those are what we might call "everyday creative moments," and I've never met a pianist who didn't do that. Even 5 year old beginners do this (unless they're taught not to, that is).
So please don't tell me you're not "creative."
And even more importantly, don't tell yourself.