At a higher level I think a lot of it comes down to what you are used to, braces vs indenting vs do/end, semicolons vs none, tabs vs spaces - but then once you're really familiar with a few languages the niggles become more focused. In some cases it's sheer amount of typing - really the only reason I don't like Java is because it gives me RSI!
This comment box is not big enough for all the things that irks me with PHP (I was a PHP dev for a few years as well and eventually left PHP for greener pastures) This post covers a big number of the things that are wrong with PHP: eev.ee/blog/2012/04/09/php-a-fractal-of-bad-design