There is no such thing as "the best anime", all you will hear are peoples personal biased opinions. With that being said, ill give you multiple options for different genres, cause ya know, the above.

Animation: that one goes to akira for me, quite breathtaking gorgeous visual, form the backgrounds to the silky smooth characters, special shoutout to the dude who had to draw tetsuos mutated nutsack.

Fun factor: Ben-to, from the makers of tje jojo animes, smooth action, impactful sound effects and just straight fun seeing people beat the shit out of each other for price reduced food

Action: Claymore, that one might ruffle some feathers, but love it or hate it, the fights are high octane, brutal and had me at the edge of my seat despite knowing the manga (especially teresa vs the other 4)

Mystery: Gosick, basically little female sherlock homes, the cases she solves are an intriguing watch if you like that sort of setting

Feeling like a child again: Little witch academia, have you ever had the feeling when you watch something it made you feel young again? be it for the setting, the feeling or just straight of nostalgia? for me LWA gave me a glint of a childlike wonder i havent felt in many years

cute girls doing cute thing: None can come even close to Girls und Panzer, adorable character design, next to zero fan service, accurate panzer action (for the most part) and the battles are just generally SUPER good

and lastly: Bawling your eyes out: Ano Hi Mita (the flower we saw that day), an estranged group of friends lost oen of their people, years later they find common ground again by trying to fullfill their lost friends last wish, i still bawl like a little baby girl who just saw spongebob dry out on the fishermans table at the ending

for anyone who finds something new to watch with this, my job here is done