I totally get that sentiment to be honest, it is very difficult to want him to do well there, same for MGW because of the nature of the defeat to Forest left a very bitter taste in the mouth. I would say in my time supporting United, post 1989, the rivalry with Forest is as strong as it has been for any team bar Wednesday. West Ham was obviously strong for years after but that has largely passed now, maybe it will with Forest but the geographical reality that we're near neighbours will always mean there's more rivalry with Forest than there is with others. You've got Derby also at a similar distance but I've never felt the rivalry for them that I do Forest. I've also lived in Nottingham and that gave me first hand experience of their dislike for Yorkshire and it does feel like they look down on Yorkshire, I have experienced that in Derbyshire and Lincolnshire saying that! It is largely banter but it doesn't warm me to Nottingham, I didn't find Nottingham a warm place to live like it is anywhere in Yorkshire in my experience, certainly South and West Yorkshire.
Forest as a club reminds me of Wednesday to be honest, but in Nottingham. I hope they're relegated this season and end up financially screwed.