Adding to this, since I posted a while back...
I only have two that aren't vastly satisfying, in that they're just tools.
But while my Savage Mark 2 is satisfying in that it's boringly accurate, my Mosin Nagant is satisfying between being an ally's (at the time) that survived 75 years in great condition and, well, the boom.
And it's not even mine, and I never expect to fire it more than a couple times, but my dad's 16-gauge Stevens 5100.
He bought it secondhand (or third- or fourth- hand; he didn't know it was older than his father), and put food on the table every year until we moved, and then when he separated from mom it went into an unconditioned storage for almost a decade.
I know I've mentioned it, but after I ran across it during his latest move to find the receiver the color and texture of a brick, the stock like driftwood, and the barrel rusted completely out, and then
reconditioning it to the state above...
The gun meant more to dad than me, but he was more proud of me the night I returned that than he'd been collectively across my conscious memory. And that association with it is the most satisfying any gun can ever be.