Haven't really got any complaints about any programming language, besides the boring boilerplate in Java. (Lisp parens repel me, but meh).
One thing that has always irked me is EJS. The angular brackets, =s and %s are not the most intuitive symbols to reach out for on a regular en-US keyboard. I find Mustache/Handlebars' braces much more approachable.
Also, adding newlines conditionally in EJS requires some really weird hacks.