Although there a plenty of other cartoons that likely win the spot of best superhero cartoon ever, you can't deny that the Spectacular Spider-Man was pretty much perfect in a lot of regards. It flawlessly bonded comic and film lore together, creating an experience that every type of Spidey fan could feel was made for them.
Tragically, it also ended early, ending in Season 2 the when Disney took control of Marvel Entertainment. This resulted in Sony giving up their broadcasting rights to Spider-Man TV shows so they could keep the rights to Spider-Man films instead.
In short, the show was the one of the first sacrificial lambs in regards to the continual beef between Sony and Disney over Spidey, which only makes it all the more impressive that it managed to do so much with only half of the time it expected to run.
With such a wild backstory, it's inevitable that wild secrets also come with the show. A mixture of its unusual production situation and delightfully creative development team means that there's a bounty of wonderful things you probably didn't know about the show that make it all the more interesting.