Why did Yaakov refer to Lavan as "Lavan ben Nachor" (Lavan's grandfather), and not, 'Lavan ben Besu'el'?
Ramban #1, Ha'amek Davar: Because Nachor, the head of the family, was more important than Besu'el. 1
Ramban #2: It is also possible that Besu'el was a nonentity, and Lavan did want people to attach himself to him, only to his grandfather Nachor. 2
Ramban #3: It may also be that the Torah mentions Nachor, who was the head of the family, in honor of Avraham, whose brother he was.
Moshav Zekenim: It is because the city was called "Ir Nachor" (24:10).
Yaakov could not mention Besu'el's name without calling him "my grandfather 3 " or a title of respect. He did not want to do so, for he was an idolater. (PF)
Besu'el had a bad reputation. 4 (PF)
Torah Temimah #1 (based on a ruling of the Terumas ha'Deshen 5 ): Because Besu'el was a Rasha.
Torah Temimah #2 (citing commentaries): Because Besu'el was not so well-known. and had Yaakov mentioned ben Besu'el, they may well not have known who he was referring to. 6
As we find later, where Lavan himself referred to "the G-d of Avraham and the god of Nachor" (31:53).
We find, "And Lavan and Besu'el answered..." (24:50). (Lavan did not esteem his father, and spoke up before him.)
It is clear that Kerem Shlomo (8:8 p. 8, cited in Daf Al ha'Daf Shabbos 33b) forbids calling one's grandfather by name without a title of respect. I did not find anyone who forbids doing so for a great grandfather. (PF)
Hadar Zekenim (to 24:33): He would have Bi'ah with every girl before her Chupah; this is why his name is like Besulah. People of his city would have forced him to do so to his own daughter; this is why he wanted to kill Eliezer!
Who learns from here that if someone whose father is a Rasha is called up to the Torah, one calls him up by the name of his grandfather - and not just by his name alone, in order not to embarrass him.
The Oznayim la'Torah adds that it is quite common for the Torah to refer to someone by his grandfather's name and not by that of his father.