I try to use single quotes as much as possible and I\'ve noticed that I can\'t use \\n in single quotes. I know I can just enter a newline literally by pressing return, but
FYI it is possible to get newlines into strings without double quotes:
printf('Please%1$sgive%1$sme%1$snewlines%1$s', PHP_EOL);
Which may be useful If your irrational fear of double quotes knows no bounds. Though I fear this cure may be worse than the disease.