What is the difference?

1.

like
as
What is the difference?

2.

like
Do you know them?
It smells like fish.
1
2
3
This man looks like me.
That man looks like you.
He works like a robot.
But he isn’t a robot.
It isn’t fish!

3.

as
He is regarded as the best student in our class.
He works as a doctor.
1
2
You are right!
He is a doctor!
3
But I don’t think you could describe him as an outgoing person.
You play the piano as well as I do!