Roxie the Cockeyed Optimist: Christmas in July

A couple of weeks ago I decided to try and improve my mood through sound. Specifically, the sound of my own voice. The theory: If we can improve our outlook through even forced smiling and laughing,as some researchers claim, then shouldn't changing our voice to a happier timbre also work?
I've been trying this and here are my thoughts so far:
1. It's still a little early, but so far I think this works better than either the constant smiling or the laugh yoga, for a couple of reasons. First, smiles and laughter are not always appropriate. There are repercussions if you laugh aloud during someone's sad story, or if you smile goofily all the time. You will be ostracized or perhaps mugged. But voice tone is something you can work on no matter the circumstances.
This sort of goes along with what I know from teaching piano. No matter what kind of a day I've had before 3 p.m., the students deserve an upbeat, positive lesson. So for those hours after school, I'm energetically and enthusiastically "on." (And this, ladies and gentlemen, is why you won't find many teachers going a straight eight hours at a time. It is exhausting.) But I don't smile nonstop--because I don't want them to run shrieking from the room. The result is, I usually feel better after lessons than I did going in, if I'd had a bad day. Maybe it's the distraction, but I think at least part of it is the vocalizing.
2.It's no easier to remember changing your voice than it is to remember smiling. I have to constantly think how I sound when I'm responding to people in everyday conversations.
3. For me, anyway, it's easier to do the voice change first. Then the smile doesn't feel so forced. It just feels more genuine, to change something from the inside and then have the outside reflect that change.

It's a little hard to say exactly what vocal changes I'm making. From various required college courses in vocal music, here are a few things I try to do:
*put my voice a little higher in my throat. Not exactly a "head" voice, but definitely not a "chest" voice. When it feels right, my voice is coming from the back of the soft palate.
*avoid a downward slide at the end of sentences (this should be a no-brainer)
*be sure to breathe. Breathing energizes singing, and playing, for that matter. So I have to make sure I'm breathing enough (again, a no-brainer, but harder than it sounds).
*try not to talk too slow. If I do, it sounds like I'm running out of energy.

I'm still on teaching hiatus, but generally, this seems to be going well. It's still a little early to say if it's working but...so far, so good.

Let's have fun for a minute.Here are some examples of Have Yourself a Merry Little Christmas, a great song because it's so open to interpretation. Listen a minute with your eyes closed and then decide which one is the "happiest" version. Which is the saddest? (How about the angriest?)

First, Frank Sinatra