In the case of Pavlov's dogs, the bell came to induce salivating because the bell, a neutral stimulus, was paired with food, a positive stimulus/reward. They learned that bell = food. But you're not going to learn, by clicking when you're happy, that click = happy. Sometimes, we come to associate a sound (especially songs) with an experience that made us happy, like an epic road trip -- and because the song reminds us of that road trip, it will give us the warm and fuzzies from now until eternity. But this isn't classical conditioning.
Here's what might work, instead:
A few years ago, I became a co-parent of this little beast:
Squirrels had never really been my thing. If anything, I'd developed a mild distaste for them during my time at Stanford, because I found Stanford squirrels to be a little... ratty.
But. I love Ruby, and squirrels make Ruby happy. Every single time she sees one, she chases it like she KNOWS she can get it this time. Even though, in reality, she probably chases 10 squirrels a day... and catches maybe one per year. That's, like, a 0.027% success rate. But her determination never wanes. Each squirrel is just as exciting as the last.
Now, because I love Ruby, and because I love seeing her happy, I naturally began keeping my eye out for squirrels anytime I was out walking or skateboarding with Ruby.
I learned that when squirrels are scared, they freeze, motionless. Then, they run to the nearest hole or tree.
I learned that it's way harder to catch a ground squirrel than a tree squirrel, because ground squirrels make a LOT of holes, and they stay very close to them.
I learned that fleeing squirrels run in erratic paths. This is because they can only run about as fast as a larger predator, like a dog -- but, because they're lighter, smaller and closer to the ground, their predators can't change direction with them. It's how they escape from bad situations.
I learned what sounds squirrels make when they're alarmed -- and that nearby squirrels will flee when they hear that sound. I also know that they twitch their tails when they feel uneasy, and neighboring squirrels notice this, too.
I learned that squirrels are liars -- sometimes, they pretend to bury food they don't really have.
I learned what kinds of yards, trees and terrains are most likely to be full of squirrels.
And! I recently learned that some species of squirrel don't like to take shelter in a small tree. That's why dogs sometimes sit at the base of a tree and bark and bark and bark. We silly humans say, "Look at that dumb dog! She thinks that if she barks, the squirrel will come back down!" But I have seen it happen with my very own eyes! Ruby was sitting at the base of a tree, barking up a storm. The object of her attention darted frantically from one branch to another, before succumbing to fear and jumping out of the tree -- right into Ruby's open jaws!
Not only does this allow me to appreciate the beauty all around me -- the feel of the sunshine on my skin; the crispness of the morning air; a silly discussion between two children in the park; a mural or flower or beautiful stranger... But it also gives me a jolt of happiness and excitement every single time I see a squirrel. Seriously, seeing one squirrel probably boosts my mood for a whole hour!
In other words, I trained myself to be more mindful. And I learned associate a neutral stimulus (squirrel) with a very positive one (making Ruby happy, which makes me happy). Over repeated trials, the neutral stimulus alone came to increase my heart rate, raise my eyebrows in anticipation, smile all crazy-like and shout, "Squirrel!"