I was enjoying the challenge, and about the halfway point I just couldn't be bothered playing any more. Not a clue why. Like a switch flipped in my mind and went "You're done with this".

I've noticed this happening to me more and more, and I'm fine with it. I used to push on with games I was clearly going cold on, because in my mind I NEEDED to finish what I'd started. But since I hit my 30s, it's like I've managed to stop lying to myself, and allow me permission to just drop stuff if I'm not feeling it. It's very liberating. Try it sometime!