With the increasing popularity of the iPhone and iPad, more and more people are choosing to take the plunge and switch from Windows to OS X. There are a number of things that behave differently from what you're used to on Windows, and it can take a while to get used to these changes. In some ways, it’s a matter of getting used to things being a bit more intuitive. Either way, the nuances may mess with your mind a bit if you regularly have to switch between operating systems. Below is a list of differences that many people have a hard time with when they first start out with their shiny new Mac.
'Close'/'Hide'/'Maximize' Has Moved to the Left
In Windows, this option is on the right side of windows. In OS X, it's on the left. It can be a bit tricky when switching back and forth from one OS to the other, and you may inevitably click something odd in the process of trying to close a window.
Your 'Ctrl' is My 'Command'
Most of those keyboard shortcuts you do in Windows (like Ctrl-C & Ctrl-V to cut and paste) still work sort of as expected on OS X, except you need to swap ‘Command’ for ‘Ctrl’. To help you remember: OS X wants you to issue "commands."
'Ctrl-Alt-Delete' is 'Command-Option-Esc'
One common keyboard shortcut that does not follow the above rule is Ctrl-Alt-Delete. If you want to bring up a window that allows you to force a program to quit, switch to Command-Option-Esc. The way you can remember this is that you're issuing the command to give yourself the option to escape a hung program. If you want to bring up a window to allow you to choose shutdown options, hit the power button on the top right-hand of the keyboard.
Use 'Command'+'Delete' to Delete Files
You know in Windows how you delete a file by hitting the delete button? OS X wants you to be a little more certain about what you're doing so you don't just accidentally hit the delete button. You have to issue the command to delete.
Use 'Command'+'Q' to Really, Really Close Programs
Here's another place where OS X will try to keep you from accidentally shooting yourself in the foot. Closing a program doesn't completely close the program. It's not going to shut down all the temporary files and things you might be working on if you accidentally click the close button, it will just hide the visible windows. You can tell an app is still open when it has a little blue circle under its icon on the Dock. If you choose Quit from the program's menu or hit Command+Q, then it'll really, really close the program.
Hit 'Space' for Quick Views
If you select a file in Finder and hit space, you get a quick preview of the contents of the file. If you wish to properly open the file with the default program for that file-type, there is a button at the top to allow that.
Don't Be Sad About Your Missing Mouse Button – Hit 'Control' and then Click
You may be getting a lot of pity from your buddies who're still stuck in Windows-land about only having one mouse button, but you can still get your context menus! Just hit Control-Click for a "secondary click" instead of needing an extra button.
'Control'+'Click' Quits Too
If you want to quit an app with your mouse instead of the keyboard, including force-quitting a frozen app, you can Control+Click on its icon in the Dock. There are a few other options in the menu item that shows up when you do this, such as showing the app’s other open windows.
Mac Takes Screenshots Aplenty
In Windows you have a special Screenshot button (called PrintScreen), and you can tweak its functionality a wee bit by pressing the Alt button. Well, in OS X you have a handful of options to choose from to get just the screenshot you want, without having to tinker with it in a photo app. MacRumors has a good guide on how to take various types of screenshots in Mac OS X. The long list of options may be a bit of overkill, but if you can memorize the key combos, it's all kinds of handy.
Find Your Preferences Under the Program's Menu
No more digging around under unintuitive menus for where the freakin' preferences menu option lives! They all live in precisely the same place – under the program's menu. Want to find the preferences for Firefox? Look under the word in bold at the top of your screen that says "Firefox." Ta da!
Drag to/from the Applications Folder to Install/Uninstall Apps
This one trips people up quite a bit when making the switch. You don't run some installer that goes through a crazy-long process to get you started with a new program. For most programs, it mounts a disk image (it looks a little like you've plugged in an external drive) that contains maybe a couple files – sometimes a readme file and always the program itself. You drag the program into your Applications folder and start it from there. And when you want to uninstall a program, there is similarly no crazy-long uninstall process; you just delete the program from your Applications folder. The end!
Login Items Are Under System Preferences
Sometimes you might want to access your list of items that start when you first login in order to see what's running or to add/remove programs. To do that, go to the Apple menu and choose System Preferences. If you select Users & Groups from the Systems section, you'll see a tab for Login Items.
Create a Virtual Windows Image
If there are still programs you still need to run under Windows, or you just need a little time to wean yourself off Windows, you can use VMware or Parallels to create a separate area where you can run Windows. Gizmodo has a handy guide of how to run Windows in OS X.