How far will you go?

When life presents an ethical challenge or choice, how far are you willing to go?

If you're handed an extra dollar in change, do you give the money back?  Does it depend on when you notice the discrepancy...if you don't realize you have the extra money until you get home, are you willing to return to the store? What if the amount was $10...or $100?  Do you roll through stop signs if you don't think anyone is watching?  Speed on the highway if everyone else is to stay with traffic?  Fudge your resume, cheat on a test or your significant other?

Does the reason for violating a rule or law matter?  Is there a difference if you embezzle from your employer because a) your kids need food or b) you think you deserve a diamond ring?  If you intend to pay the money back, does that make it ok?  Or if your chances of getting caught are very slim?

By nature I'm a goody two shoes, a stickler for the rules. Whether I agree with some of them or not, they're there for a reason...such as maintaining order or sustaining the common good.  But some people believe rules don't apply to them. 
Going by the book may also go against the grain.  Taking the impact of your actions on others into account isn't always easy. 

Garrett Hardin's tragedy of the commons theory resonates with me.  Simply put: if everyone who gets a new a cow puts it in the town pasture to join the cows already there, at some point the munching cows will deplete the grass.  Then all the cows will starve.