People think I need the last word, but I don't understand why I'm perceived that way

Recently, two things occurred in my personal life that brought about this idea that I always need to have the last word or always think I'm right. A university friend I hang out with is known for his argumentative nature and academic attitude. No matter what I like or what my opinion is, he'll always take the opposing opinion and consider his knowledge 'right.' I'm gay and we argued about gay representation in the media, and the entire time I was trying to portray an opinion of representation not being explicit. He got so frustrated that he said (in a mocking tone) "you always have to be right." But this came after he ignored my opinion and called everything I show interest in "superficial" and without deeper meaning.

Today, one of my friends hung out with someone that I have not talked to since high school. We used to be super close, but when we graduated he stopped talking to everyone. Now that he's started talking again, he's told people he doesn't like me anymore. Everyone is taken aback by this, and his reason is that I talk to much and always think I'm right. But I never remember actually getting into any arguments with him about anything; we were good friends and to this day I hate getting into conflict.

What is happening? Am I really portraying myself as egotistical without knowing it? I am genuinely confused and would love some advice about this conflict.