As a computer nerd, I really felt like AMD was on it's way to great places in the early 2000s and believed in their product over Intel, as most of my friends who built their rigs were leaning towards the former. Alas, I couldn't have predicted them fizzling out so badly after the mid-2000s.
I've found that my weakest bets on fundamentals are with tech stocks. With anything else, I'm right as much as I expect to be - about 50% of the time.
With tech, I find I'm much closer to being wrong 80% of the time. I think our knowledge of the industry makes us believe we have more information than everyone else, and thus that we're in a better position to make bets. In reality, the things we know that your average investor doesn't aren't as crucial to the bottom line.
http://www.pcpro.co.uk/features/372859/amd-what-went-wrong