No I am not kidding, Lupin the 3rd is the greatest anime of all time.

Some context is needed.
Lupin the 3rd was written by the late manga writer Monkey Punch way back in 1967 and to this day still exists as one of the longest franchises in Japan with the anime alone surpassing 50 years of service, only Sazae-San and Astro Boy can claim longer innings, but while Astro Boy has a very stop start history and Sazae-San's history is a post war manga and an anime that never ends, Lupin the 3rd has been consistent in every generation of anime from pre otaku era of the 70s, up to modern day with no sign of running out of steam but there is more than just longevity, it's got itself a unique legacy with two very well known people in the industry, Hayao Miyazaki and Shinichirō Watanabe.
Miyazaki needs no introduction, the Lupin film Castle of Cagliostro was the first film he worked on as a director which jump started his career proper.
Watanabe directed Cowboy Bebop often called the best anime of all time and cites Lupin the 3rd as his biggest inspiration.
That's already a big boast and we haven't got to the actual anime yet.
Lupin is an anti hero with a goofy front but extremely clever skills always keeping you on your toes.
Jigen is the straight shooter who goes along with anything but isn't afraid to shoot to kill.
Goemon is the noble samurai who maybe takes that honor a bit too seriously but is very capable of some super human feats.
Zenigata is a bumbling interpol detective but is actually very capable outside of going after Lupin.
Fujiko is not only the first waifu and sex symbol of anime but has infinite lore.
There are very few episodes that doesn't have you compelled to find out what happens next.
It might be formulaic but there is enough in universe too keep going, even others in it's genre like Detective Conan and Cat's Eye have crossed with the phantom thief.
Ontop of everything, Lupin also manages to age well, keeping a fresh animation style, working in CGI and even live action.
The only thing he couldn't do, was convince the estate of the Arsene Lupin author to use the name Lupin but that's a story for another time.
Take this with a pinch of salt though.
I don't begrudge MAL or IGN for constantly showering praise on Full Metal Alchemist Brotherhood, it's still a great anime. Cowboy Bebop set such a high standard that still resonates today, even all the shonen, the stylish look of Jojo, the decades of experience Sazae-San has, the impressive legacy the Pokemon anime has and even my own favourite anime Black Lagoon all are just as capable of being the best and there's no stopping them from achieving that because what's really important is what you consider the best.
Take all that subjective thought out, and you can see it better when you take everything into consideration even then, you will probably disagree and l accept that.