How do I preserve my art when I press "save as"?

In every other software I have ever used on computers, after I press "save as" I can create a file for my work, close the document I am working on, and later open the file exactly as it was when I pressed "save as". 

When I press "save as" in Illustrator, I close my work, come back later to open the file, and it is vastly different. Some parts of my art are still good, other parts are gone or severely distorted. If there was one text box with text, sometimes it has become many text boxes in different locations with different fonts.

Saving in Adobe is convoluted. There are so many technical options and document setting options that it is not user friendly for a typical person who simply wants to preserve what they've created (though I am sure it makes perfect sense to the programmers and people with years experience using the software). I think I am a fairly intelligent person and am generally able to figure things out for myself, yet I have no idea how to save my work in Illustrator so that I can reopen it and start working again where I left off.

There needs to be a save button that automatically preserves the work as it is without a thousand technical options to navigate, but also keep those options available for people who have specific purposes for their work.