What makes this game so great is that the side quests are so much more complex than most open world RPGs. Where most games side quests consist of fetch quests and kill 10 pigs or generic crap like that. The Witcher 3 instead, has fully fleshed out stories for side quests that have narrative arcs, character development, and twists and turns not usually found in most side quests in games like it. This aspect alone makes the game feel so alive and interesting. Along with this, the combat is great, the main story is superb, voice acting is top notch. I can't really think of anything negative about this game to be honest. Definitely one of the best open world RPGs ever made.