This parable is shared by Tim Ferriss in a podcast which used by American politician Newt Gingrich to know the productivity of a person.
A lion is capable of hunting both field mice and antelope. If lion chooses to hunt field mice to satisfy its hunger it will provide only temporary satisfaction. But in long run it needs more energy to survive.
On the other hand if lion chooses to hunt antelope which is bigger than field mice it’ll serve the hunger needs of lion for a longer time.
This is simple distinction of priorities we choose. If we choose something for a temporary satisfaction in life-like eating field mice we’ll miss out the long-term benefits of eating antelope.
Whether in job or life it all comes to one thing are you planning for future or are just getting with the present.