Everybody always talks about the human brain as a supercomputer, but it is actually incredibly slow. The speed at which signals travel through the brain is about one millionth the speed of signal transmission in computers.
Despite this, you are able to recognise a face, a song or even a smell instantaneously, whereas it would take a computer that is technically much faster, much longer.
This seemingly paradoxical speed is likely to do with the brain's ability for parallel processing, but even this in itself is confusing.
The problem with running lots of computations at once is that it gives you lots of different results. This is the thing that slows down parallel-processing computers, but the brain is somehow able to sort through all of these at lightning speed to produce one single thought, behaviour or memory.