If you know the type of games I like, it won't come as a surprise when I say that I loved every minute of Grand Theft Auto V. The cinematic storytelling style of Rockstar gets better with each iteration and the acting is top notch. I always enjoy their action-movie type stories and the addition of multiple protagonists was a refreshing improvement to the formula. Watching the story unfold from each one's perspective was interesting and the three of them were fun to play in their own way, but the times you control Trevor, or even just when he is part of a scene, were the highlights of the game for me.
I'm sure it would have been an even more amazing experience at launch but, despite having played it a few years later, technically it's still a very impressive game. The map is huge and detailed and the visuals really hold up... it looks great. And, when it comes to the gameplay, there are a ton of missions and almost all of them are quite entertaining, especially the heists. I loved the bank robbery in GTA IV so, although most are not that intense, having more missions of that kind this time around was fantastic.
Probably the best game of its genre I've ever played.
More info: https://en.wikipedia.org/wiki/Grand_Theft_Auto_V