I like to think it depends on the situation. I don't expect the worst from my children, wife, career, health, etc. Maybe after so many times of being let down by something you love then you put up that imaginary wall. Where the Blazers are concerned, i am definitely in the "I don't want to be let down, so I expect the worst" category.
Drafting guys with known injuries
Keeping a coach that has only been out of the first round in 11 years, and never with us
Seemingly not having a direction when it comes to style, players to add to the team
Horrible PR moves