What You Aim At Determines What You See
The world that you perceive will shift around you based on what you aim at. This is part of your biology: it organizes your perceptions of what you see and don't see, and your emotions and motivations, based on what your goals are. Put another way, what you see is all there is.
An example of how this biases our beliefs is when we see arguments from one side only without seeing proper arguments from the other side. We end up viewing that side as being stronger, and are unable to truly see the other side as it was not properly represented. The antidote to this is to find common middle ground and expose yourself to disagreements that are done in true good faith from the other side.
Whether you have a positive growth mindset where you believe you can grow or a negative one, what you aim at determines what you see and to a large extent determines where you go. It is better to aim low but up. As long as you are focused on an upwards trajectory, you will see opportunities to get better that you would have missed if you had a negative mindset.
This all requires discipline, as you cannot aim without discipline.
References
12 Rules for Life by Jordan Peterson
Deep Work by Cal Newport
The Realignment #121 | Julia Galef: The Path to Thinking Better with the Scout Mindset
Thinking, Fast and Slow by Daniel Kahneman