Used to work as a dishwasher at a local Chinese food restaurant while I was in high school. I was told that there is a right way and a wrong way to open a fortune cookie in order for it to "work". Now, the following is from memory and not Google, and I may have it a little wrong, but...
You never open one until the meal is 100% complete, you are supposed to break it and eat only the lesser of the two halves you create, and you can't look at the fortune until that half is swallowed. Once you read it, you cannot read it aloud and must pass it to whomever is interested in seeing it and they can't read it aloud. Finally, if you do not touch the cat statue (at least one found in every REAL Chinese restaurant) on your way out and thank the host (matradee, owner, main dude) for the meal while looking into their eyes in a heartfelt manner, it won't come true.
Something about respect, honor, and tradition.
I assume you followed correct cookie protocol?