For anyone who has enjoyed sitting down and watching a few episodes of NCIS, you'll know that the comfort of the show comes from its very well written cast of characters. From stoic Agent Gibbs to bright Abby, the show's long running status has relied on comforting characters who we love to bring us back and back again to the otherwise fairly standard procedural. Now coming up on its 21st season, most of the original cast has departed, but there has been one semi-constant, the guest appearances of the now-late David McCallum's Doctor Mallard a.k.a. Ducky.

Now I haven't kept up with NCIS for years, but my fond memories of the show all have to do with Gibbs and the arrival of old friends. Mark Harmon's lead agent Leroy Jethro Gibbs is a bit of a loner, having pulled away from the world after his wife and young daughter were murdered. At work and elsewhere, he's quiet and reserved, and doesn't talk about his personal life or his past. Of course, this means that all the young agents at work speculate about him. And that speculation runs rampant when someone old enough to know things appears. This comes most often with Gibb's old senior agent Mike Franks (played wonderfully by Muse Watson) and Ducky, the chief medical officer of NCIS.

Now Ducky is eccentric, that's for sure. He wears bow ties and talks to dead bodies. But what he also brought to the table was something the other characters couldn't bring. He brought his wisdom as well as shared time. He wasn't put off by Gibbs' standoffishness, in fact he could see through it. He was an old friend, after all. And in staying with the show NCIS for more than a decade, even as a guest, he brought that level of old friendship to the screen. He became our old friend too.