I've never been very keen on going to the dentist. As important as I believe dental hygiene to be, I've come to associate my visits with the dentist with bad things: some level of discomfort, perhaps even pain, a flossing lecture from the hygienist, at the very least. Most of which is readily avoided by doing the things I know I should be doing regularly – brushing, flossing, a better diet. 

And knowing that I haven't done what I should have been doing, I have good reason to believe that my visit to the dentist will be a negative experience – and so I put it off. 

However, it's not as though the postponement makes the situation any better; if anything, the delay makes the eventual "confrontation" with reality worse. That's what retirement planning is like for many: They know they should be saving, know that they should be saving more, but, despite the encouragement of plan sponsors and advisors, they hesitate to go through the process of a retirement needs calculation because they are leery of the "pain" of going through the exercise itself, or perhaps even afraid that their checkup will confirm their lack of attentiveness to their fiscal health.