Simplistic vs Simple
Simplisticadjective
characterized by extreme and often misleading simplicity
Simpleadjective
having few parts; not complex or complicated or involved
The difference
Simple is neutral or approving — uncomplicated. Simplistic is always a criticism — oversimplified to the point of being wrong.
How to keep them apart
Never reach for simplistic as a compliment. It says the thinking left something important out.