Everyone responds differently to information overload, and individuals with conditions such as autism can be especially sensitive to it. Therefore, the subjective condition of the person is as important as the amount of informational stimulation that they encounter.
Regardless of how rational or high-minded you try to be, you cannot make decision after decision without taking a toll on your mental health. This is different from your ordinary physical fatigue as you are not consciously aware of being tired, but rather you are low on mental energy.
The more choices you make throughout the day, the harder each one becomes for your brain to process and inevitably it will begin to look for shortcuts to limit the amount of energy being used. One shortcut is to become reckless: to act on impulse instead of thinking through the consequences. Another shortcut is the ultimate energy saver: To do nothing. Rather than mulling over decisions to be made, your brain takes the easy way out and just simply avoids any choices. Unfortunately, by nothing, this causes bigger problems in the long run despite easing any mental strain you have at that moment.