He was clearly insecure and very caught up on his own title. It is noticeable, also, how futile he is.
"He had been a collegiate assessor for only two years and therefore could not forget it for a single minute. To make himself sound more important and to give more weight to his status he never called himself collegiate assessor, but ‘Major’."
You might say that he was proud of his rank because of the following text:
"He did not so much mind people making personal remarks about him, but it was a different matter when aspersions were cast on his rank or social standing."
But in the end, he would even change what to be called to make himself more important, showing again his own desire of being more than what he is, his insecurity and futility.