I'm not going to spend hours just staring at scenery, my back catalogue of games to get through is too long to spend so much time on one game. Of course I will do side missions, but we were specifically talking about completionism, which is something else.The main storyline is quite long and the cutscenes are worth watching. Its a slow paced game for the most part and I would be surprised if anyone just got on with it and didn't spend hours just hunting animals or seeing the sights.
Always something going on like most Rockstar games.
Some of the side quests are well worth doing.