I always want to like the Witcher series, but I can't get into the role of Geralt. I can't connect to that character at all for some reason.
Generally, I prefer to play an anonymous protagonist so I can make my own story out of the gameplay, but Fallout 4 has you play a pretty specific person and it didn't put me off. Plenty of other things were off-putting about that game, but not that aspect.
But for some reason, I can only play the Witcher for about a half hour before I feel completely disconnected from the experience. The same thing has happened to me with all three entries in the series - I reach a point pretty early on where I start to realize that I don't really care about the character or anything he's doing.
It's a super popular series, though, so it's definitely me not them.