When I think of Nebraska fan's delusion it's not delusion in the sense of we think that we field a better product on the field than reality shows us. If anything that's the opposite - everyone, especially on messageboards, is quick to believe our team is far more awful than they actually are. Remember the absurd and unfounded predictions of how we'd get scorched by five touchdowns by halftime against Georgia?
I think of our delusion as one of a delusion of grandeur; collectively, we tend to think we are far more important (read, not talented or superior performers) in the scheme of college football than reality shows us.
This has been proven in this thread, really.
"ESPN hates us". No. ESPN doesn't really care about us; they care about themselves.
"Kirk Herbstreit hates us." I mean, if anything, he's fond of us, but generally he's probably not that worked up in thought over us period.
"People are butthurt because we won their competition or we beat them" Usually, they either aren't butthurt at all, or if they are, part of it is because we're insufferable.
Thankfully, there are plenty who disprove this theory; especially on Huskerboard, but there's plenty of legitimate reasons why so many other programs can't stand Nebraska or it's fans, and believe it or not, it's not entirely jealousy.