Character determines what success is allowed to turn you into.

Success is an amplifier rather than a maker of character. It provides room, options, and fewer constraints, and whatever was already there expands to fill that space. The person who was quietly impatient becomes visibly so; the person who was generous becomes more able to be. Nothing new is created, only enlarged.

If things are going well for you, watch what is growing along with them. Ask someone honest whether you have changed and listen without defending. And if success has not yet arrived, work on what you would want amplified, because that is much harder to install afterwards.