Attempting to drift off to sleep and heard in my head a middle-class brit rather sternly saying I was "continuously too selfish to humanise the letter" what does this mean

Also on Tumblr, Pixiv, InPrnt, Newgrounds, Artstation, Cohost, Inkblot and twitter to varying degrees.
Attempting to drift off to sleep and heard in my head a middle-class brit rather sternly saying I was "continuously too selfish to humanise the letter" what does this mean