What if, asks philosophy students everywhere, the real world isn't actually real? If it's a dream, a simulation, or otherwise entirely imagined? What consequences should this have? How would it affect your lives?
Well, this completely destroys the very concept of consequences. Any mess of any kind I leave behind can be deleted from the situation, declared invalid, or forgotten until it ceases to exist. Cleaning? Why bother, leave the area and it gets done for you when the simulation or dream forgets it existed. Insult someone? It can be erased from their memories, or otherwise deus-ex-machina'd out of existence. Or, if you control the simulation, the very person can be removed. And if you don't, avoid them until whatever's controlling the simulation forgets that they should be mad at you.
As a simulated person, your goal is to entertain whatever's operating the simulation. You should do things that are interesting to it as often as possible, so as not to be ... stopped. All simulations have a cost, computer simulations have a processing-power requirement, dreams need brain and time, and other simulations, too, require resources. Whatever's paying the bills had better be satisfied with your behavior, or everything you know ends abruptly.
Of course, if you're wrong about this, this means that you'll behaving like an insufferable bastard for no good reason, and while amusing to watch from a distance, will enrage your entire family and friends and suffer numerous consequences in the name of comedy.
Although many philosophers speculate that it is quite likely that we live in a simulation now, on the grounds that computing power is continuing to increase all the time, and simulations of past events are becoming increasingly common, therefore it is likely that you are actually a simulation, run thousands of years in the future for historical purposes.
However, as a counterpart to this, I note that I "live in the future" as it were (my computer would have been thought of as massively impossible even 100 years ago), and I do not bother to simulate the lives of my medieval ancestors. Just because I have the power to, doesn't mean I necessarily do it. I'm more likely to simulate something that never was, or even never could be, than the actual factual past.
Since I believe that the amount of computing power to simulate my life exactly won't exist until 2500 at least, and because I think 1980 - 2009 will not be the most interesting set of years from now until then, I sincerely doubt that my life is simulated. So no wild goofball behavior for me.