"But he did it too!" isn't a justification to your parents when you get in trouble, and it doesn't work much better in the office. If these rules exist but are enforced selectively, you have to ask yourself, "Why did the company feel the need to enforce them for me and not others?"
You got caught, you need to own up to it and move on, not get indignant and make things worse.
Managers don't want to be policing their employees, preferring that the employees use common sense to make enforcement unnecessary. For instance, managers would rather employees be allowed to use Facebook on work computers, so long as they get their work done, since trying to police who is using Facebook is tedious and will only grow ill-will.
Unfortunately, someone ends up playing Yahoo! Chess all day and doesn't get any work done, and the company institutes a policy against it, and the manager is put in the unenviable position of having to enforce a rule put in place only because one person needs to have a rule to reign in their bad behavior.
There is give-and-take in enforcing any rule in the workplace. If you don't want to run afoul of the rules, use common sense to make it easier for the manager to overlook the issue than to try to enforce it against you.
Rules are Rules
You admit you broke the rules. Whether or not other people are doing it is irrelevant to whether you broke the rules. For whatever reason, the rules were selectively enforced in your case. It would be wise to figure out why. Here are some possible reasons.
Your coworkers may have a better working relationship with your manager.
Perhaps your manager felt you were trying to play lawyer with the rules rather than just apologizing and moving on.
Maybe your manager had been giving you a lot of slack and hinting that you were pushing the line, and this was the last straw.
Or maybe it was just that your quality of work isn't as good as your coworkers, and so they got off easier because they're seen as more valuable.
What can I do so that the same rules apply to me as they do everyone else, or that the same rules apply to everyone else that do to me?
- Apologize for the infraction
- Accept the discipline
- Improve your performance
You got caught. If you haven't already, apologize to your manager. Don't make excuses, don't try to justify, don't try to explain, just apologize. You know that the bus route is long, but aren't leaving earlier to make sure you're on time -- that is 100% on you, it has nothing to do with your coworkers or your manager.
Accept whatever punishment is given to you. It is penance for breaking the rules. Disputing it, fighting back against it, or otherwise raising a stink will spit in the face of the apology and make it seem like you just don't understand why you were punished in the first place (this invites more selective enforcement and punishments in the future).
Use this as motivation to improve your relationship with your manager, your value to the company, and your performance in the job. Show that you may make mistakes, but that those mistakes will teach you to be a better more valuable employee in the long run.
And don't even try to bring up what your coworkers get away with. It will not impress your boss, and it will not impress your coworkers.
Hey boss, sorry I was late today. My commute is really long, and it is on the bus which is unreliable, so it isn't really my fault. I mean, how can I control whether the bus is on time? Most of the time it isn't a problem! So I'm really sorry, but you see, it wasn't my fault! And anyway, John and Jan were also late with far worse excuses. It isn't fair that you are getting me in trouble for this and not them!
Hey boss, sorry I was late today. I'll take an earlier bus starting next week to make sure it won't happen again.
My commute is really long, and it is on the bus which is unreliable, so it isn't really my fault. I mean, how can I control whether the bus is on time? Most of the time it isn't a problem! So I'm really sorry, but you see, it wasn't my fault! And anyway, John and Jan were also late with far worse excuses. It isn't fair that you are getting me in trouble for this and not them!