Catching Up With The Lingo

I've seen the term "jumped the shark" around, and I even gathered what it meant — if only from context at first. But no one seemed to be able to explain the "why" to me. Thanks to a co-worker, I learned it's a reference to an old episode of Happy Days.

Of course, in my most recent blue funk, I have to wonder: at what point did my life jump the shark? Is there a defining moment, that, if handled differently, would have produced a significantly better path than where I am today? Is a better path even possible, or is this as good as it gets?