Four Prime Time Soaps. One friend.

[Jimmy Todd]

Random observation on an early morning commute: Of the four big prime time 80's soaps, was Dallas 'Muriel the only "friend." I don't any of the other shows had a character who appeared as much as she did just in the role of Lucy's friend. She as minor a character could be while still being a somewhat regular. She even figured into a finale in that she was the one Lucy confided in that she had been raped.
Ok. Jock and Ellie had Mavis and her husband, so maybe Dallas did a little bit more than the other three to convey that characters had an existence outside of the main cast.
Characters such as the occasional "Bobby's from college" don't count because they were just in and out plot devices.
One of the more amusing things about soaps is when they had a bachelor or bridal party and the only ones in attendance were the members of the main cast. These were people the groom or bride to be rarely ever saw or with whom they were feuding.
KL was a bit more honest about it. When Abby told Olivia to spend time with her friends, Olivia responds that she has no friends. Abby smiles and says, "Neither do I."

 

[Mel O'Drama]

KL was a bit more honest about it.

A case could be made for Knots doing the friendship thing more than the others. The difference is that we saw these friendships - whether it's Val/Laura; Richard/Karen or Mack/Ben - from the inside out, rather than the other way round.

The others did this too, of course, but in storytelling terms Knots was a lot less dependent on outside confidantes because the setup was community based rather than familial. For every character's storyline, there were usually always several other characters who could either look at another character's storyline with some degree of objectivity or, alternatively, were kept outside of that storyline altogether.

In Dallas, Muriel was almost an avatar of the audience, on the outside gasping at each new revelation she discovered, while always remaining removed from it and somewhat passive. This was important because it added a relatability to a series where main characters were so involved in the soapy stuff it was the norm. Over on Knots, main characters could step back from it once in a while and react to the soap norms as we would: and so you have Mack monologuing to himself about everyone on the cul-de-sac being a basket case, Olivia quipping about Abby's penchant for eyeshadow or returning Richard observing the increased wardrobe budget with his "no more polyester knits" line.

 

[Daniel Avery]

In the early seasons of Knots Landing, Diana had two female friends, Brenda and Ellie, we saw intermittently. They were typically brought in when Diana was experiencing a 'teenage storyline' like being pressured to have sex with her boyfriend, or to offer someone for Diana to talk to. Brenda was played by Helen Hunt, and Ellie was played by Wendie Jo Sperber, both of whom went on to substantial acting careers as adults.

My personal favorite in this category of characters is Marsha, usually seen as Karen's assistant. Though technically an employee of Karen's, we never really saw her doing anything but hanging out with Karen and organizing takeout lunch orders for them. She worked at Knots Landing Motors, Lotus Point, and was around during Karen's time hosting Open Mike, though I don't think Marsha worked for the TV station, per se. She was just....around all the time. IMDB even credits her portrayer, Marcia Solomon, for appearing in 28 episodes!