Personal Statements

I wonder what everyone thinks of writing personal statements. I mean how often do you have to trace back 4 years or a lifetime of work and reaccount everything you feel is valuable. Doesnt it devalue your accomplishments if you constantly have to sing ur own praise? Or is it a sign of confidence that you know what u've done right?
I haven't gone to Africa to txt malaria or anything, i'm just too ordinary, so my ps looks bland. (i really wish i could go to africa and txt malaria or HIV but then would i really write about it in my ps? wouldnt that cheapen the whole experience? )
I couldn't find too many examples essays to go by, I might just post mine up soon, it just needs an ending. Here some websites i found:

http://www.scutwork.com/cgi-bin/links/page.cgi?page=Statement&d=1
this was good overall , no specific examples but gave a good framework

http://webcampus.med.drexel.edu/osa/careeradvising/pssample.htm
I think this is some of drexel's sample ps, they seem decent, but a bit preachy
Also as in most of these "examples", person A has been a PT for 10 years, person B is AOA and made their own clinic in their spare time.. so not exactly real life for 99% of med students who spent most of medical school .. studying.