I won't argue I'm "bitter" (whatever that means) but I'm certainly not angry. Most of the time I'm just very, very disappointed.
You should take a look at my perspective. I indulge others in conversations and participate in debates with them, hoping for some intellectual discourse. I give them the benefit of the doubt. I want to be proven wrong or to educate them. Both are great for me, as my goal is mainly just conversation and the promotion of knowledge/truth. The resulting conversation is sometimes just to find out they literally do not even comprehend what is being discussed, do not even attempt to communicate by trying to understand other's points, and often seem to be making all kinds of irrational assumptions that have absolutely no bearing on the conversation. (The majority of the time I argue with someone, they don't even seem to comprehend what the conversation is about...)
After some talk and they still seem confused, I even give them the benefit of the doubt that they are just stupid or incompetent and I go about explaining things as simply or repetitively as possible. There is little else you can do. You cannot reason with trolls, you cannot have rational conversations with people controlled by extreme cognitive biases and close minded predispositions. Sometimes I try to have fun with them after I realize they just trolled me and wasted my time and thoughts. It's the least I could get from them after their lunacy.
It's all pretty pointless because the entire conversation was a sham from the start. They never had any intention of listening to anything anyone else had to say, and just wanted to argue for the sake of arguing.