As we have seen in the popular series like Naruto and One piece where protagonist can't remember the name of opponent and even if they do, they mispronounce it.
So I searched for the tropes and got to know about Malicious Misnaming.
A person dislikes another person and repeatedly, intentionally calls them a name to rile them up, specifically a mutation of their own name.
This definition might hold true for some part, where protagonist intentionally use it. Which doesn't for the series like mentioned above. They do actually forget or mispronounce the name unintentionally.
Not only protagonist but other character do show these characteristics, like in Gintama where most of the time they are for gags(gags jya nai katsura da).
So I want know about the tropes if there is any one. And why they have these characteristics. Are they only for the gags or for the other reason. Like protagonist remember opponent's name when protagonist finally accept as real opponent.