No Annoying Pop Up Windows

Here's an intermediate (but easy, trust me) tip. When you change a file type name, for example a .jpg to a .gif, Mac OS will ask you if you're sure you want to do that. Not only are they slowing me down by making me click another box, but it makes me think, "If I have gone through the process of clicking on a file, retyping an extension, and pressing Enter, don't you think that's what I meant to do?"

But there's an easy way to disable this. Open Terminal (it's in your Applications > Utilities folder, or you can simply press Command + Space Bar and type Terminal) and cut and paste the following piece of code after the $ symbol and press Enter:

defaults write com.apple.finder FXEnableExtensionChangeWarning -bool false

After that cut and paste the following and press Enter:

killall Finder

That's a very medievally satisfying one to paste. Now you won't get those annoying little pop up windows anymore. Thanks to Cult of Mac for this tip.