Hmm. Not sure. Where are you up too?
A lot of the original seasons had somewhat filler episodes. But seasons like Rebooted and Skybound are a must-watch.
There are 74 Episodes and two 44 minute Specials
EDIT: Completely missed the line that said you stopped after the first year.
So was it the Skeletons or the Snakes?
Might as well start from the beginning.
Special - Ninjago Masters of Spinjitzu
Ep 1 - Rise of the Snakes
Ep 7 - Tick Tock
Ep 10 - The Green Ninja
Ep 12 - Rise of the Great Devourer
Ep 13 - Day of the Great Devourer
Ep 19 - Wrong Place, Wrong Time
Ep 20 - The Stone Army
Ep 22 - The Last Voyage
Ep 23 - Island of Darkness
Ep 24 - The Last Hope
Ep 25 - Return of the Overload
Ep 26 - Rise of the Spinjitzu Master
That's pretty much the first two seasons.