Many newcomers dislike Emacs’s default behavior of not indenting automatically new lines in programming major modes. Usually one has to press Return, followed by Tab to open a new line and indent it according to its context.

Of course Emacs has a command named newline-and-indent, that’s bound to C-j and many people are into the habit of using it instead of the pressing Return + Tab. Some even rebind Return to newline-and-indent.

(global-set-key (kbd "RET") 'newline-and-indent)

What’s little known is that Emacs 24.1 introduced a new global minor mode called electric-indent-mode. When enabled, typing certain characters (like newlines) triggers reindentation. So you can simply add this line to your Emacs config to get to enjoy electric-ident-mode:

(electric-indent-mode +1)