It is not bitter to feel aggrieved when someone screws you over or treats you badly, constantly makes fun of you, etc. It's not even bitter to feel hard done by when things go against you, or to feel misrepresented by a biased agenda led media.
Bitterness is getting everything you want, and still being bitter about it, like a spoilt child.
Bitterness is winning and rubbing it in other people's faces because you have no concept of joy or happiness, because your entire existence is based on getting one over on someone else and gloating about it.
Bitterness is winning a trophy for the 1st time in 30 years, and the 1st thought is to celebrate outside the Headquarters of your rivals, and vandalising landmarks for daring to be there.
Bitterness is getting to a European final, being interviewed on TV and gloating to a group of supporters who weren't even in the competition.
Bitterness is choosing to support a side who have won more than virtually every other team in the country, and being bitter when anyone else wins anything.
Bitterness is constantly needing your collective egos fed, ramming it down everyone's throats for decades, but being offended and getting hyper defensive when anyone dares to suggest any negative behaviour from your players or fans.
Liverpool have far and away the most bitter, twisted, selfish, miserable, mean spirited, saw loser, ungracious winner, perennially offended, condescending, glory hunting, classless, immature, childlike fanbase there is. It's not even close. And that even that goes for former players as well, who have infiltrated every and all avenue of media to help push the propoganda.
The only reason you call Everton bitter is because all of the above is true, and despite all the trophies, you are jealous of what makes us special.
It's an absolute fallacy that Everton are bitter, and one that has been peddled for decades to excuse your own childish behaviour. It's literally the only comeback you have.
But the more you peddle it, the more it proves my point.
Enjoy your hollow victories and your gloating. I know it won't bring you any true joy.