A Good Work Experience

I completed a job assignment to day The first contract job ever in IT

I would say it went well and I learned alot.
I made a good impression on the people there but I may have talked a bit to much
They may hire me again to do other stuff

It is some what a weird thing to fight against the past decisions and do what is ethical only I was able to control all internal desires and only do the job I am proud of myself
I must be vague here for legal reasons but I am changing and it is about time.
By stopping and picking up some money I also conquered that little beast inside me today too.

Why did I feel so guilty about charging him money for the work I did ?