Why would you want to convince yourself in the first place?

Mostly because it'd be more surprising! At the moment I can't predict I'd be convinced by an argument, but a future in which determinism turns out to be the wrong model of the world would definitely be interesting.

Like if there's some sort of ending to all of this and you discover that there's this thing called "free will" which you were judged by the whole time?

Kind of, but my sentiment is a little more meta. A deterministic universe is easy to reason about. Of course there's a huge amount of emergent complexity we still don't fully understand, but I think in the broad strokes, I get it and that's that.

But a universe with free will? All bets are off. Your comment I'm replying to is just a hint at "thinking through the implications". People are scared of determinism, but a universe built on free will is actually absolutely wild.

So, if you and I agree that the unknown (e.g. the future) is exciting and worth hanging around for, wouldn't that be kind of exciting too?

This is more or less also my take on religion. Nothing has convinced me of superior beings, but if it were to turn out there actually are some? Ho-ly shit.

Well, honestly, I have never found a great argument either for or against the existence of free will. You'll hate the basis on which I believe in it because it is so terribly tautological.

I believe I have free will because it appears to me that I have free will.

Because I can't make a solid logical argument either way, I believe the thing that brings the greatest amount of joy to me. I never forget that there's an asterisk on this belief, though, and am ready to abandon it should an argument come along that removes ambiguity.

But I also believe that "belief is the death of intelligence", and so use "believe" as shorthand for "have as a working hypothesis".

I mean, this is actually fine. I also don't know another modus operandi than living life like I have free will. I still sweat decisions. :-)