The parts of XSLT that cause me problems are the functional programming parts; not every problem is well-suited to functional programming, especially when it comes to, as in that case, parsing complex interconnected documents to find information

So your example of how 'functional programming fails' is to use a vague personal anecdote about possibly the worst 'functional' language in the world, many versions of which don't even have higher-order functions which is a basic key functional feature dating back literally to the 1960s, and of which people have published research papers just to prove it is Turing-complete?

Do you understand why no one is going to find your claim that "functional programming sucks because I once wrote a bad program in XSLT" even remotely convincing? Even if you do boast about yourself that

I'm not hired to solve elegant problems. I'm hired to solve the problems that companies have spent 20 million dollars to fail to solve.