It can be difficult to see it for what it is because its most common form is as a bias, which can be very difficult to discern, even within ourselves. ( Daniel Kahneman and many others have done amazing work about unconscious / barely conscious biases ). I never saw it when I was younger because I didn't think about it; I didn't even know that it was something I should be thinking about.
I'm somewhat ashamed to admit, but I've felt it myself. I remember when I was still very young, maybe 20 years ago, we had a "much older" guy join my team at work. At first, I felt a pretty strong internal resistance to working with him, never mind that he was brilliant and deeply experienced... he didn't even play videogames! But he was funny too, and he taught me a hell of a lot. He managed to give me advice that really helped my career, plus he knew tons about money and credit and investments.
It took me quite a few years to realize that the 'internal resistance' I felt was solely due to his age. It's a good thing my Mom taught me to respect my elders. Those lessons have served me well.