Most areas of the world use at-will employment but I'm specifically familiar with the US and Canada. In either of those you can kill options dead due to expiration clauses[1] - actual equity issuance tends to be rarer due to the tax liabilities around it and, either way, dilution can destroy your value and it's completely legal. Additionally, if you crunch for work, you can be denied promised bonuses[2], be fired before they arrive[3], or just be suddenly downsized and end up needing to eat that bonus while you find another job.
Do not work overtime without compensation, no company is your baby and companies have no legal obligation to remember your service. Labour laws are terribly slanted against employees so be very conservative about your expectations from work and never sacrifice your health (mental or physical) due to some B.S. team oriented camaraderie.
I work hard at my shop, I really love all the things we've managed to accomplish and I appreciate all the folks I've built them with. But when it comes to money it is good to be incredibly self-interested because no one else will do it for you.
1. You can be put in a position where you're able to exercise your options but you'll be doing so blindly - trading personally held cash for stock and hoping the company doesn't end up tanking.
2. Bonuses are almost never legally promised in practice, so they remain at the grace of the employer.
3. At-will employment laws means that all future implied payments can be retracted if employment is terminated excepting those that are contractually owed.