A few months back, a colleague and I started training in a very competitive graduate programme. While working in the same city, each of us would be based at a different centre: one at a nationally recognised institution that arguably is the more prestigious place to work and train, and one that is more peripheral and probably less attractive to employers. Because I scored marginally higher than him on the entrance exams/interviews, I had first dibs and naturally chose the superior place (the commute was also way better for me honestly). Because he already had some research links at this place, he was quite put-out to be sent to the other centre, and at times it was maybe a bit awkward between us, but I took precedence here and I figure that's just how it goes.

Then, we found ourselves standing against the other to be the student leader of the academic course. In a bizarre and kind-of unprofessional arrangement, people had to verbally vote for who they wanted and explain why. I won the vote almost unanimously, and it was a bit of a cringe-a-thon basically. While we never argued or anything, it was kind of obvious that we weren't going to get on too well and generally stayed out of each other's way. He did drunkenly have a bit of a go at me in a taxi not long after, but I was drunk too and earlier that night I'd (accidentally) knocked his drink all over him and things were a bit high-strung with exams and stuff.

So skipping forward a few months. Working at this big centre, I've talked to my workmates about all this, and this enmity between me and him has kind of become a running joke. I haven't made stuff up or anything, but I've sort-of painted him as this bitter and unpleasant guy, which is only half-true really. When he came to my department for a meeting the other day pretty much everyone had lined up behind me and were definitely cold to him- not horrible, but way chillier than when they met me. He is also a really masculine, muscly Russian guy- I am a gay British guy who is arguably much more savvy about office culture and how it works. While I'd never play "identity office politics" or anything, I think most of the staff have judged him before meeting him, and I haven't really made any effort to stop this. 

There is one job at the end of this programme, decided by the staff at my centre. Am I the asshole for cultivating a certain attitude towards this guy in my workplace to ensure I have the best shot at a job, or is this justifiably cutthroat?