These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ensemble Darkhorse: The Daltons sometimes became even more popular than Luke. In fact, in the Xilam Animation produced series "Les Dalton", Lucky Luke doesn't even appear, and the focus is on the Daltons as they try to escape from prison.
Rantaplan, to the point he got his own series;
A minor exemple with Calamity Jane.
My Real Daddy: The majority of the fans refuse to acknowledge Laurent Gerra as Morris' successor.
Technically, Laurent Gerra is the latest of the numerous Goscinny's successors, while Achdé is pretty faithful to Morris' drawing style.
Replacement Scrappy: A rare inversion; the second set of Daltons have ended up becoming much more famous and iconic than the original.
Seasonal Rot: When Morris died and the series was written by comedian Laurent Gerra.
Villain Decay: The Dalton Brothers have suffered quite a bit of it over the years. In Les Cousins Dalton, their 1958 debute, they get the best of Lucky Luke, forcing him to service for a time. Within the story each brother is given different character traits. Joe is the mastermind, William is obsessed with guns and using everything on sight for target practice, Jack is a master of disguise. Averell is naive but also a superb boxer. In fact he fights Luke to a standstill. Luke only wins by using his cunning, not his fists. The two combatants agree to meet for a rematch and retreat to their own rooms for sleep. Only Luke manages to releases mosquitos in Averell's room. The following day, Luke is fresh after a good night's sleep, Averell has not managed to sleep at all. He can barely walk, much less fight. Since then, several stories portray them as incompetents.
"Weird Al" Effect: At least in Francophone Europe, the Dalton brothers from Lucky Luke are much more recognizable than the historical Dalton gang.
YMMV items from the movies:
Big Lipped Alligator Moment: In Go West: A Lucky Luke Adventure, there is a woman who sings a musical number that has no relevance to the plot.
Most prominently, the Game Over screen, where you first see someone pointing a Gun at Lucky Luke's back (a Continue Screen available only in Sheriff mode) and then shifts to Barnaby the same-as-always undertaker as he holds his hands in cynical delight, with a poster reading Game Over (in typical "western" font). Can easily become High Octane for the most sensitive.