They can't by definition BE fortune cookies without some bad ones as well. Doubly so because of the whole Chinese Yin/Yang thing that specifically applies to Chinese fortunes and astrology as well.
edit:
My (female) friend says to always add "in bed" to any fortune cookie.
The ones on my desk right now:
"Put up with small annoyances to gain great results"
"You will be joined with an old forgotten friend"
"You could prosper in the field of entertainment"
