Excellence Is In the Details: GMail EOM
It always gives me such great pleasure when I notice excellent attention to detail in software that I use on a daily basis. In this case, it's a detail that I've noticed before, but never have heard anyone talk about.
Every once in awhile I send someone an email with just a subject line. If you enter a subject in GMail and hit send, you'll get a warning dialog asking if you really want to send without a body.
However, if you follow the convention of suffixing your body-less subject line with the string [eom] and hit send, then GMail doesn't bother prompting you with the warning dialog, because someone on that team knew that EOM stands for "end of message".
Excellence is in the details. They don't always have to be visible or even talked about. In fact, when you discover those great little details in practice it can really be a really delightful and loyalty-building experience.