1. Overthinking things can lead to paralysis
Often times, people who want to think big think too much. Overthinking is when you spend a lot of your time thinking about everything and maybe even worrying about every detail, which can lead to overload. Overload can cause you to become paralyzed in your ability to produce whatever it is you are working toward because you can't focus on one thing at a time.

2. Big thinking might be overwhelming
The inability to focus on one thing at a time then becomes overwhelming. Overwhelming feelings might lead to frustration and a breakdown of the path you want to be on.

3. Big thinking might lead to a big failure
Now, I know that big thinking can lead to big wins, but I also believe that big thinking might lead to a big failure. Just because you are thinking big does not mean you will succeed. You might
fall flat on your face.
Big thinking could also cause you to move too quickly or take a step in the wrong direction and lead to a big failure. I guess that is a chance you had have to take, but having a big failure might lead to paralysis and fear of moving forward.

4. Big thinking might be too far in the distance
Sometimes the big thinking is too far in the future for you to get a good sense of it all. This might lead to poor decisions. It is great to have a long-term goal for your future, but thinking big might just be out of reach at the moment.