Searching through random piles of LEGO bricks is a good training for the brain. It enhances the pattern recognition abilities that are useful in many situation. With the huge variety of different colours those bricks come from it also helps becoming better at distinguishing those colours.
I used to think of colours at their basic form. There was only blue, green, red, yellow and so on for me, not bothering about all the different hues. When I restarted my LEGO hobby I was overwhelmed by all the colours. I couldn't tell the difference between colours that were similar. It didn't help looking for reference from the screen as the colours don't always look the same there and the names didn't really tell me that much.
It's a lot easier when you are building a set out of the box. There usually aren't bricks with too similar colours in a set so it's easy to pick up the right ones. But when all those bricks are mixed up together the similar colours are all there. I did quite a few mistakes in the beginning, but now I'm starting to distinguish most of the colours apart from each other. I can also identify the right bricks just by the name of the colour most of the time. There are only a few colours that I'm still struggling, but those are mostly the ones that are actually physically really close to each other.