:dancing-banana:
Why get upset? Did you react out of fear, (ie.,nearly caused an accident?) or was it pure anger that someone would get ahead of you? It seems to me I'd prefer a road raging driver ahead of me where I can watch him, than on my tail. Yes, I think it was a sin since you came from Mass and, likely, Communion. Whether mortal or venial, ask your priest. Perhaps you should have a Crucifix where you can see Our Lord as you drive. When tempted, look at Him and offer it up. Why waste an opportunity to gain graces? If God sends you crazy drivers, accept them as His gift. Continue praying for therm, but definitely quit returning the anger. "A mild answer turns away wrath..." Proverbs 15:1