@Background Pony #C36F
Basically any Spike focused episode from season 7 onwards as his progress was violently backtracked and he was made a blithering idiotic buffoon.

What is this referring to specifically?

Spike’s face here  
“I am so going to get back at you for this if I survive, Twilight! BIG TIME”

@Daneasaur  
I’m just going to address/add something about Spike and The Crystal Empire.
 
If we’re getting technically about each character’s role then there were three main players:
 
Twilight:  

@Crowley  
The only reason Spike is lauded as the hero of the crystal empire is due to Twilight outright lying. Twilight told shining, cadance, and everyone else that Spike did EVERYTHING inside the castle, which is a total lie. He helped by getting her away from the door, then he got the heart and promptly fell off the castle. The reason Twilight made such a lie is due to self depreciation since Celestia said “you must do this alone”, but she didn’t do it alone (she had all 5 of her friends, spike, shining AND Cadance helping), but because she fell into the second of Sombra’s traps, she felt she had failed and told everyone that “Spike did everything”.
 
And don’t get me started on equestria games.
 
But anyway, lets focus on Spike episodes with important milestones in them:  
Secret of my excess:  
Showcased that, while he likes all the mane 6, even Twilight doesn’t touch his heart. The ONLY thing that stopped his rampage was his love for Rarity and realizing that being the greedy monster was going to ensure she hated him.
 
Dragon quest: While a… very bad episode overall, Spike learns the cardinal lesson that it doesn’t matter about your blood ties, but about those who love you and who you love in return.
 
Inspiration Manifestation: Spike caters to Rarity’s inner desires, but when she goes too far, he puts his foot down and breaks her trance, willing to risk her not liking him anymore just to ensure he does the right thing and returns to her normal self.
 
Dungeons and Discords: While most see it as a Discord episode, Spike personally sasses him with little remorse and eventually forces him to see that they were just trying to invite him for a good time if he could just look past his ego.
 
Times are a changeling. Spike’s hero worship is all over the place, but the ground up relationship he makes with Thorax is so honest and pure, he is willing to be labeled as a traitor to equestria should they not accept that he and Thorax are friends. Results in a key moment that prevents the whole of equestria from being conquered by chrysalis.
 
Gauntlet of fire: Spike had every reason to not compete, but instead did so when several dragons mentioned attacking ponies as soon as they got in charge (one over pillows). Spike’s actions saved Ember’s life, ensured a compassionate (if potentially unfit) leader was in charge that would at least consider friendly relations.
 
Once Upon a Zeppelin: A short scene, but Spike shows marked understanding of Twilight as well as what her paperwork consists of, forcing her to go on vacation while he handles her busy work.
 
We can also include many of the smaller bit part scenes in numerous episodes where he is correcting Starlight in what she should be doing, teaching entire classes in friendship school, and so on that show he has a SOLID grasp on real world dynamics and isn’t a buffoon.
 
These are IMPORTANT milestones that have a prominent effect on the character and ignoring THESE to make him a blithering idiot and to recycle a plot from a previous episode leads to what infuriates the Spike fans so much.

@Background Pony #0171  
That fandom logic.

I bet you’re fun at parties, OP

@neo4812  
Dude. She’s the princess.  
She owns the whole damn kingdom.  
Including that statue.

@Crowley  

 
Sorry sweetie, but that episode was… kinda boring

@Crowley  
Candance helped with that so where’s her statue?

So has everyone just forgotten about this or what?  

I’m sure he’ll get an episode where he gets to shine

This is the main reason why I don’t even like watching Spike episodes anymore.

I too like to assume negative scenarios in my head then get angry at other people for the negative scenario I made up.

I hope they fucking prove it wrong…

sadly true

This is sadly accurate.