BYU fans.  Most do not hestitate to either talk about BYU in glowing terms or otherwise talk trash like: "I'm from Logan and love the Aggies."  I've never had a "BYU sucks" or "I only go there because I have to" kind of response, though.  

I remember seeing other students wearing UU stuff here and there when I was at BYU.  I never cared enough to even think about it.  I don't recall having the same kind of animosity toward UU then.  I was too focused on my studies, job, dating, and life to get too invested.  I went to games and cheered wildly for BYU but for those attending with me who had other fan based alliegences - to each his/her own.

One thing I would have NEVER done as a missionary would be to go into someone's home and say something negative about their alma mater, their fan alliegences, etc.  Our job as missionaries was to work with, build up, and love the members - as well as the local community.  Talking trash of any kind in a home - especially when getting to know people - would have been taboo.  Why risk alienating yourself by saying stupid stuff?  But, I have noticed that many missionaries today do not follow that protocol.