A bathroom thought

Last night, we had a problem in the house...plumbing problem. I was up all night. Finally, I caved in for my wife's opinion and called a 24 hrs/day plumbing service. After paying $220 for 25 minutes work, I finally went to the bathroom.
As usual, a thought came across to me. I remembered how in the old days we used to throw some rice for the pigens to come and feed. I also remember seeing lots of bird feeders at work and many places. We have one too in our backyard.
I then started asking myself...oh wicked self...are humans good by nature or bad? Are we good inside of us and express it by doing something that we gain nothing out of, except bringing some happiness for other creatures (as in bird feeding). Are we naturally good, but sometimes we exhibit bad behavior (abnormal to our nature) as in not feeling responsible to help other human beings?
Or we are bad and evil by nature, yet we go out of our ways sometimes and feed some birds here and there.
This is like looking at the glass half full or half empty. What are we? good or bad, by nature. And of we are good, then why do we exhibit so many bad behaviors for our fellow humans.
If we had no religion..and no laws whatsoever...would we revert to the evil nature or simply the good one? If murder had no punishment..or adultary had no consequences...or beating up humans had no consequences...would we still do it? We all know that adultary is not allowed in islam, yet, in heavens, the rewrd for some is 72 vergins. We know that drinking is not allowed, yet in heavens, there will be rivers of wine. We are asked to pray 5 times a day, yet, no prayer is asked from humans in the heavens. Is this a sign that humans are bad by nature, and that we have to go out of our ways (and be good) to get the promissed rewards?
I hate bathroom times...it has a toll on me.