Earlier today, I gathered with some friends to get our Smash Bros on (the game came out yesterday). Compared to my friends, I'm clearly the weakest player, and playing this game a couple of weeks earlier with them got me spiraling in a depressive funk. I knew one friend was good - as in, practice a LOT good - so winning against him was nigh impossible. Very often, a fresh version of my character would pop in when he's at 5% damage, and I'd be knocked out without me laying any additional damage on him. And yes, it got frustrating.
So playing again with the same group, I certainly feel a tad pessimistic and not excited to be losing again. But I've acquired some more dodging skill after a day of playing, so maybe I may have a chance.
However - HOWEVER - I made the most of the situation, and started to be come very elusive with my newly-acquired dodging skill. Next thing I know, I'm deftly avoiding attacks, air-dodging projectiles, and side-stepping people's punches and kicks. I started cheering myself for being so nimble on my feet, so much so that I forgot completely when I was knocked out of the match early on. All of a sudden, playing Smash Bros was fun again, and I found myself smiling once more.
No, not THAT.
I guess the biggest thing to draw from this Smash Bros example is that fun is pulled from your own personal goals. I hated losing, but that's only because I was focusing on winning. The moment I started making my goal to NOT be on the business end of my friend's powerful attacks, then suddenly I found myself achieving that goal much more to my satisfaction and amusement.
Yeah, it's essentially a goal to "suck less," but a goal like that really can only lead to gradual improvements down the line.
The same can be applied to board games. The goal shouldn't really be to win, but to figure out what will give you the most fun. Many games offer ways to induce this feeling, and successful ones will have everyone enjoying themselves, without any regard to who wins or loses.
And really, that should be the thing to beat.