Fans included Reddit have expressed their annoyance at the show’s treatment of Sam Winchester in particular, stating that it’s obvious (especially in later seasons) that the writers favored Dean and always seemed to give him the most relationships with supporting characters. “One of my biggest pet peeves [is that] Sam has very few interesting dynamics throughout the show, especially compared to Dean,” wrote u/Ultra_Amp. u / Terrestrialwho explained, “Jensen would basically get all the secondary character relationships…yeah, that bothered me.”
Even Jared Padalecki has drawn attention to Sam’s apparent lack of close friends on the show, though he believes there’s at least a good reason for that. During the panel JIB Con 2018Padalecki explained that Sam is “an intellectual … he finds solace and friendship in books and studies, and likes everyone around them, but he’s also a little more reserved.” The actor talked about how (in the past) Sam lost almost everyone he was close to and that that experience led to him becoming so withdrawn in the first place.
Padalecki’s comments make it clear that while Dean certainly has more friends than Sam, this is more the result of their different personalities and not necessarily the result of unfair treatment by the writers.