The language itself is not that bad. Especially the newest releases are really great, thought out DX improvements. What stinks are its legacy parts and how it needs to be run.
My biggest pain is that for it to actually behave like it should it requires some sort of an actual web server like apache or nginx.
Also, servers written in are actually request handlers - every time a request comes, the whole app is reinitialized, because it just can’t hold its state in memory. In many apps every request means reinitializing connection with database. If you want to keep some state, you have to use some caching mechanism like redis or memcached.
Also had one time when Symfony app was crashing, because someone forgot to close class braces, and everything was “working” until some part of code didn’t like it and was just dying without any error.
And one time when someone put two endlines after php closing tag at the end of the file, confusing the entire php interpreter into skipping some lines of code - also without warning, and only in specific php version.