You come home from a funeral, you are emotional and upset.
A family friend puts their arm around you and comforts you
You must go to bed with them straight away, it's the law in soap opera land!
To balance that though, in soap operas if you have an affair you are guaranteed to get caught. Nobody ever gets away with affairs. And you're probably going to get humiliated in the pub in front of the locals
Soap characters also seem to have no problem sitting drinking in the local pub with their ex husband at one table, their ex lover at another and the parents of the guy who murdered their son having a bit of banter up at the bar.