Despite all the memes and criticism of the series(alot of which is valid) we all keep coming back to Pokémon, so let's take turns explaining what we liked about each gen. I'll start.

Gen 1: Sense of discovery was unlike other gens because we didnt know what to expect. Legendaries weren't hamfisted into the plot.
Gen 2: Overworld and sprites were comfy also great music. Best rival in Silver.
Gen 3: Probably my favorite soundtrack of any Gen. It also introduced double battles which is my preffered competitive format.
Gen 4: Another great soundtrack. Phys/Spec split was a godsend. Infernape in 1st Diamond playthrough was the clutchest in game mon I've ever used. Still have it to this day.
Gen 5: Had a different feel from other Pokémon games. PWT was really fun. Best Bike theme. Snivy is my favorite 1st stage starter.
Gen 6: Best online ever hands down. Super training and amie were also fun. VGC 2014 was a great format. Greninja is my favorite 3rd stage starter.
Gen 7: Ultra Beasts were awesome and refreshing. Torracat and Dartrix are my favorite 2nd stage starters. A good gen overall in terms of design.