I just finished Stumbling on Happiness by Daniel Gilbert. Took him a while—even with considerable inspiration from Shakespeare—to get to the gritty nitty, but the gist is that when conjuring the future, the mind is phenomenal at compensating for unknown details—filling in the blind spots. Your brain takes the few facts that you do know and flavors them with your current mood. The "after"—for better or for worse or for humdrum—is pretty much out of the picture. We rarely question the semblance. We take the mind's prediction as gospel, and bank our happiness on what often ends up being a lot of really good hocus pocus. [Those with lobotomies need not worry...well, you probably can't. Damage to the frontal lobe impairs a person's ability to imagine the future.]
When given a choice between information about an event/experience and testimony from someone (a "surrogate") who's already been there and done that, people want the information. Those who are given a surrogate's testimony are more likely to accurately predict how they'll feel afterwards. Apparently, we all would probably be more happy if we were more willing to learn from other people's experiences, BUT we don't because we think we're sooooooo special. Despite the preponderance of similarities, other's experiences couldn't possibly apply to us.
I think Gilbert has some good points. How crafty is the gray matter and how easily duped we are! Even so, his premise was a little pitchy for me, dawg. (Sorry. Just got done watching American Idol.) Acting on another's testimony may be effective in some situations. (Is this milk sour? Will it satisfy me? Here. Take a swig and tell me how you feel afterwards.) Informing your choice with other's experiences is also wise. But there are times when you just have to take the leap by and for yourself...sans surrogate. More often than not, I think I'd just as soon stumble.