Personally speaking, apart from perhaps one example I can think of, I don't. Within a couple of weeks, especially if a pint's involved, apologies are said and we're back speaking again with the spat consigned to the past. I just don't have it in me to hold on to such resentment and the old adage about life being too short certainly rings true.
Even on here, which shouldn't be taken seriously anyway, I'll call someone a wanker one week and then green them the next. Although there's more emphasis on the wanker if they happen to have a propensity for sky blue and/or don't worship at the altar of OLEgend.