I'm thinking of manipulating other people
Why would you manipulate someone?
I lie to manipulate them for my own benefit
Manipulating people for your own benefit is selfish. It makes you a bad person. You should treat others the way in which you want to be treated.
I'll still do it without fail.
It doesn't matter if you think you can get away with it. Manipulating others is fundamentally wrong. If someone were to learn of what you did then they would become very angry with you.