I enjoy their sibling relationship because it feels real. It's not stale or wavering from episode to episode as some plot device. Lynn's relentlessly on Lincoln's case and some siblings are just like that.
Opinion respected, but I don't like most of their interactions. Everytime Lynn and Lincoln are on-screen together, especially in recent times, it almost feels like an unfunnier Ernie and Bert or Bugs and Daffy shtick.