Not all people will always agree on every point and for that matter may vehemently disagree on many things. We are all different and that is the way we are the same. Diversity makes the world more interesting. With that said grudges are something that doesn’t need to exist and in fact make life complicated and ugly.
You never know a year from now if you are faced with a wonderful proposal to start a new project or business and there is your nemesis! If your past argument ended on a friendly note, then there may be a chance that one or both of you forgot what the confrontation was even about. At the least it won’t matter and you can try to work together and maybe even laugh about it.
On the other hand if it ended on the ugly side you probably need to move along and find some people to work with who you have more in common with? This can prove to be very embarrassing and will limit your chances. It would also be very disappointing to you (maybe both) if you realized on the spot that a possibly great opportunity will be missed due to some petty argument in the past.
This is just another reason to always keep an open mind. Do not ever limit your options by being stuck to a way of thinking that cannot be changed no matter what the logic may be. Sometimes it is much easier to consider the other person’s point of view and unless it is something so radical as to be in your opinion morally or ethically repugnant, at least think about it and be gracious in your refusal.