simple in not easy

Often times, we use easy and simple interchangeably, however they are not same.

Easy is relative: I might find rock climbing hard, you might find it easy, you see ? It is relative, me not knowing piano does not make it hard.

Easy is nearby: Something that is physically close or handy. It does not mean its simple.

Easy is familiar: I might know C programming language and say it is easy because its within my skill set. It does not mean its simple.

Simple is

How can we fix problem in it if we need to ?

How can we enhance it if we need to ?

Does it do what it is supposed to ?

Is it reliable ?