Good question, Warriorstrike.
(This is what creativity means to me, in my own words)
What is creativity?: Creativity is imagination going in different directions. What I mean by that is when you think of something, it is combined with all sorts of things and shapes. Some people may not be as creative as others, but that does not mean they cannot be creative or are not. It is not only self expression, but it is the way your mind puts things together in an artistic way. For example, I am a creative person, and when I do something creative in a dance I do it to make things become more interesting and beautiful. :3
Is creativity same for everyone?: Honestly, no. Everyone has a different way of being creative because their imagination is different. Some people don't have a strong sense of creativity, but they are still creative. But others have stronger sense of creativity, so if they were to do something amazing on a paper their skills may be better.
What makes you decide if something is or isn't creative?: Well, since this is linked with art I'll go to that side. When people do art, you may consider some as bad art or good art, but even if you think that it is still an art. So if you were to say someone or something is not or is creative, they are always going to have creativity because people are not in the same levels.