At my last gig, part of our business process was to generate a unique human-readable ID that could tie an individual to our product and service. Well, we had a few rather superstitious, paranoid and vocal customers who felt 'uneasy' when they received their unique ID with 666 in it.

So after having a good laugh and roll on the floor, I got to write an exorciseUniqueId() method that compelled the evil numbers to stop possessing those innocent IDs!