In a book due out this month, Stop and Sell the Roses (Ballantine, $25), entrepreneur Jim McCann of 1-800-FLOWERS reports that the $300 million flower-delivery company was often inundated by phone calls, particularly during key holiday periods. McCann knew that customers of his Westbury, N.Y., company were irritated when calls were not answered by the third ring. But he also knew that callers disliked being put on hold. The solution? Lengthening the time between the start of one phone ring to the start of the next -- from six to nine seconds. That change gave the company more time to answer the phone within three rings. Customer interviews determined that callers didn't notice they were waiting longer, and the solution cost virtually zilch.