I’ve been a victim of this awhile ago, I think another side effect of this is that people with certificates automatically discount your knowledge because you lack the said certificate.
I’ve encountered this with managers from job listings for java programmer, web developer, database administrator and the like.
I sometimes had to restrain myself from correcting people who were interviewing me. Its a balancing act between not seeming arrogant whilst trying to correct a false assumptions. I find this often with people not that passionate with programming and the like.
as a disclaimer with everything I write: What Do I Know I Am Probably A Big Fool!

Dunning-Kruger effect

From Wikipedia, the free encyclopedia

The Dunning-Kruger effect is the phenomenon wherein people who have little knowledge (or skill) tend to think that they know more (or have more skill) than they do, while others who have much more knowledge tend to think that they know less.