Don't count your chickens before they hatch.
It's a silly saying, really, because if you've got a bunch of eggs that might hatch into chickens, you really should count them, to make sure you have enough heat lamps, and chicken feed, and chicken water bottles, a big enough properly-fenced chicken enclosure, and your chicken veterinarian on speed-dial. It's probably also a good idea to count them so you can tell if anyone is stealing any eggs when you aren't looking.
This isn't the first time I've been this close to a job. I've even been this close to a job with this particular company before. I know how these things work. But that knowledge isn't going to stop me from getting excited about it. I need to be ready to leave my current job with no hard feelings, and be physically and mentally ready to take on the new job.
What the maxim should say is don't count on your chickens before they hatch. Don't make purchases based on the money you expect to get from selling them. Don't depend on the chickens hatching. And don't spend your every waking moment counting them or blogging about them, either. You have better things to do.