When you reboot your laptop, all the processes in your RAM are wiped off, the RAM is cleaned up and then the computer makes a fresh start.
That allows it to work smoothly as compared to when their RAM is overloaded with multiple processes.
Our brain is no different because it is one of the most powerful efficient computers on earth. And, to allow it to make a fresh start we got to reboot it.
Nature has given us the gift of sleep which works as a natural reboot for the brain. But we, human beings, are known to push our limits and at times we don’t pay attention to this natural sleep signal.
When we don’t sleep enough our brain slows down and it also hangs at times, like when we just go blank and are not able to understand anything at all.
If you continue on this mode for long our system can crash which is best avoided.