How we cite our quotes:
"You, Gregor!" cried his sister with raised fist and piercing eyes. These were the first words she had addressed directly to him since his metamorphosis. (2.26)
Finally, somebody says something to Gregor, but it's not a good thing. Grete throws his name at him as if it were an insult instead of a mark of his identity as her brother. This passage looks ahead to Part 3, where Grete refuses to call the bug "Gregor" and insists the family must find some way to dispose of it (see Quote #8 under "Family").
[His father] was holding himself very erect, dressed in a tight-fitting blue uniform with gold buttons, the kind worn by messengers at banking concerns; above the high stiff collar of the jacket his heavy chin protruded; under his bushy eyebrows his black eyes darted bright, piercing glances; his usually rumpled white hair was combed flat, with a scrupulously exact, gleaming part. (2.28)
Like Gregor in his military days, Mr. Samsa feels empowered in a uniform. The fact that it's a bank messenger uniform doesn't seem to matter – Mr. Samsa's still the man. His erect posture and vivid facial expression starkly contrasts with Gregor's abjectness.
In the beginning she also used to call him over to her with words she probably considered friendly, like, "Come over here for a minute, you old dung beetle!" or "Look at that old dung beetle!" (3.8)
With the exception of Grete's calling out Gregor (see Quote #4), nobody calls Gregor by name again. The only person who says a word to Gregor is the cleaning woman, not any member of his family, and she calls him a "dung beetle." It's probably not as insulting if you actually are a vermin, and even though Gregor is annoyed, he detects the cleaning woman's "friendly" intent. It does make you wonder why the cleaning woman of all people should be the only character who makes such gestures to Gregor.