If you want to bring out the best in you then you should look for the difficulty and not the accessibility. Let's face the fact that easy things will give you no improvement, it will only make you feel good but not great. Doing or pursuing easy things will put you in the rank somewhere between mediocre and average. Don't get me wrong, there is nothing wrong with that especially if you are truly satisfied in your position. But what if there is a place in your heart, maybe not big but there is a small place in your heart that says "I am sick and tired of just being another human being". What will you do?
You should look for someone or something that will bring out the fire in you. It can be a situation, a person or some kind of a challenge. How to know what it is? very simple, it gives you strong emotions, it gives you excitement, fear, joy or motivation.
If you are an athlete and you feel unchallenged not because you were already great but you feel there is something lacking in your training or daily routine then it is time for you to look for a person that will bring out the fire in you. The best person would be a nemesis or someone who is stronger than you. Build a silent competition. Compete against him without him knowing it. Watch his actions, training and goals then be greater than him. In this way you will be forced to make yourself better than yesterday. You will be hungry in training again and you will have goals for yourself. You will do whatever it takes to become stronger than him. The best part here is if he didn't know it then it will be lesser pressure to you.
Look for something that is very hard to achieve. It can be being number one in your class, aiming for your first million, being a CEO or president of the united states. Whatever it is that excites you, go for it. Never care if that challenge is big or small, what matters is it will make you go a little bit uncomfortable. If you don't feel uncomfortable then it it is not challenging and you will not grow. You will have no fire in pursuing it because you already knew that you can get it without exerting too much effort, the competition already died before it happens. The fire that was supposed to come out from you has already been extinguished. The lava turns into ice.
There will always be someone or something that will bring out the best in you or the fire in you. It is your duty to find it if you are feeling that you are lacking some motivation. It is everywhere. Anything can become your motivation, anyone can become your rivalry. This is one good way to expand yourself. This will make you move and leave your weak and old self.