I think of you as a brother.
(You remind me of that inbred banjo-playing geek in Deliverance.)
Theres a slight difference in our ages.
(You are one jurassic geezer.)
Im not attracted to you in that way.
(You are the ugliest dork Ive ever laid eyes upon.)
My life is too complicated right now.
(I dont want you spending the whole night or else you may hear phone calls from all the other guys Im seeing.)
Ive got a boyfriend
(whos really my male cat and a half gallon of Ben and Jerrys).
I dont date men where I work.
(Hey, bud, I wouldnt even date you if you were in the same solar system, much less the same building.)
Its not you, its me.
(Its not me, its you.)
Im concentrating on my career.
(Even something as boring and unfulfilling as my job is better than dating you.)
Im celibate.
(Ive sworn off only the men like you.)

… and the number 1 rejection line given by women

Lets be friends.
(I want you to stay around so I can tell you in excruciating detail about all the other men I meet and have sex with. Its that male perspective thing)