Most people want to be good at something in their life. A smaller fraction have the desire to be great. It's the difference between using a ruler and measuring tape.
To be good is to have excellent flashes of measured performance here and there. To be great is to sustain that excellence over long periods of time. Lebron James has been in the NBA for twelve years and is widely considered to be the best player in the game. His consistency shows in his numbers, but even moreso in his ability to win. Good authors might see a bestseller in their lifetime. Great authors will be around for generations. Good parents try to be there when they can. Great parents rarely miss a moment.
Greatness is hard. If it was easy, everyone could do it. I think everyone gets there in different ways, but most hit on at least these key ingredients: Consistency + Sacrifice + Failure + Coachability. I find the first to be most important and something that challenges me on a regular. Am I consistently working on my craft to improve it day in, day out, no matter how I feel?
Consistency is why we root for certain people, why we stay loyal to certain brands. You know that person or brand will rarely let you down and, when they do, you can rest assure it won't happen too many times down the road. That's something I'm wrestling with on a daily for I know my consistency will help elevate me from good to great. Just have to be willing to put in the work.