Bubble

The term bubble, as I use it, refers not only to the economic bubble in which the valuation of some tech start-ups went crazy but also to the mindset of the people working inside tech companies, the true believers, and Kool-Aid drinkers, the people who live inside their own filter bubble, brimming with self-confidence and self-regard, impervious to criticism, immunized against reality, unaware of how ridiculous they appear to the outside world — Dan Lyons

This was me just a few years ago