This is more of a trick question. Assume the worst, buddy.

If you assume the best in people, all you will see is what you expect, and the bad in people.
If you assume the worst in people, all you will see is the best in people, and the neutrality.

If you expect people to do good things, the moment they don't live to that expectation, you see something bad about them.
If you expect people to do bad things, everytime they do a good thing, they prove you wrong.

Everything is evaluated on what a person does and what a person does not do.

Of course, in the end run, it makes no difference, since using either method, will still lead to the same conclusion.