Ninjago is a great show to watch because each season teaches a great lesson and the story is interesting (and super awesome too!).
The writers of Ninjago have thought carefully about the story of Ninjago (e.g. why the villains became evil, why the heroes became good, why there are sometimes cliffhangers at the end of each season) and they do take their time to make each season as best as they can, even if it takes nearly 1 year! You can relate to the characters because they have personalities that people in real life can have and although Ninjago is meant to be a kids show, anybody aged 10+ who likes epic action, meaningful story lines and unexpected backstories for characters might like Ninjago!
The newer the seasons, the more complicated and serious the stories of Ninjago. E.g. there used to be slightly more than 10 characters in season 1 whereas there are probably about 30 characters or more in the whole history of Ninjago.
You can find seasons 1-6 of Ninjago on Netflix and you can find all of the seasons of Ninjago (seasons 1-9) on Cartoon Network. You can also find some episodes of Ninjago on Youtube, but I'm not sure if all of the episodes are available on Youtube. You might even have to pay real money to watch some episodes of Ninjago on Youtube.
Ninjago must be watched in chronological order, otherwise you will not understand the story. If you found my review helpful, then perhaps you can please try to look for Ninjago episodes now! Maybe you'll have an awesome experience you won't forget!