What is funny is one of the WORSE fanbases towards Tennessee is actually Vanderbilt fans. They are not much of them and they fall into three major categories:
1. Vanderbilt fans who also cheer for Tennessee (they are basically fans that like college sport and cheer for Vandy because they are local to Nashville but would probably be UT fans if they were in Nashville. I have a story bout this one).
2. Vanderbilt fans who hate everything related to University of Tennessee and will bandwagon on any team that is regularly beating Tennessee (i.e. Florida in 1990s, Alabama under Saban, I think they are jumping on Georgia right now)
3. Vanderbilt Alumni who are real fans
I used to go to the Tennessee-Vandy game every year when it was in Nashville as a kid because it was your chance to see Tennessee in Middle Tennessee. One year when Vanderbilt started winning, I saw a bunch of fans in front of me wearing orange and they took it off and had black and gold Vandy gear under it. No joke. They were Vandy fans from category #1 listed above.
They use the excuse that Tennessee fans will attack them at the game if they don't wear Orange lol. However, they are not afraid of Tennessee fans if Vandy starts winning.
Vandy has a lot of fair weather fans and they bandwagon on anyone that can beat Tennessee. They also brag about Academics when they lose even though most of them never went to Vandy and couldn't get in anyways.
Alabama fans have really been on another level of crazy this year. I think they were a little softer on Tennessee fans (as long as you didn't mention Fulmer) because they were beating Tennessee soundly on a regular basis. However, when Tennessee finally won a game, it was a major meltdown. I even saw Bama fans bandwagoning off Georgia's win over Tennessee.
Georgia fans have a special hatred of Tennessee. I remember when they beat us in Knoxville when I went to school there and they were the worse fan base out of all of them (Auburn came in at #2). I never really quite got it.
@WhosYourDawggy references some bad Tennessee fans in 1990s, maybe that was the case. I always considered Alabama or Florida to be more of our rivals (and Kentucky. Arguably, Kentucky should be our biggest rivalry as we have played them more than anyone but they are usually not that good at Football. Last few years have been an exception). However, both Auburn and Georgia fans really want us to be one of their most hated teams so I guess we have that.