Oberyn disappointed me. An experienced fighter would not have been killed that way. Even MMA do not make such mistakes. Always ensure that the enemy is incapacitated. He ridiculed Tyrion's lack of fighting experience, only to be killed by an error that screams immaturity.

It was a fitting end for him though. He was whimsical and careless. No matter how much skill you have, you will die with such qualities in battle. I really liked Oberyn. It is unfortunate I am disappointed yet again (as always with many other characters) by his stupidity.