Sneaking into a second movie: super-wrong or harmless fun?

It's not super wrong, you're stealing services you didn't pay for🎥. 

Several times, I asked the manager and was given the OK.

It may not be super wrong. But it is wrong never the less. In some areas of the country you can be arrested on "The  Theft of Services Laws". Same laws used to convict those skipping out on a restaurant or a hotel without paying their bill. Not worth it around here.

Super wrong? No, it isn't like someone died. But it is still wrong. It taking money from a business that has to pay rent, utilities, taxes, and operating expenses.

Well I learned something new today. You may be charged with theft or trespassing.

http://blogs.findlaw.com/blotter/2013/06/can-sneaking-into-movies-get-you-arrested.html

Just like stealing from Walmart.... It makes the prices go up for the rest of the paying customers! :0(

It's wrong.  Just buy another ticket.

Temporary conversion of material?  Theft of intellectual property?

Not the best way to practice getting away with something.

That tends to blur some important ethical distinctions with distinct edges that you may wish you had available to you later in life.

Taking something that doesn't belong to you is theft. A movie theatre sells tickets in exchange for the privilege of using their facility to watch a movie .. If you don't pay, you are stealing that privilege ... So, to answer your question .. YES .. It is super wrong!