Start from nothing. No shared state with previous requests. Plough right through as many errors as you can. Log them, but don’t stop. Keep executing code until you run out of things to do.
Fail-fast leads to more stable systems.
WhatsApp famously runs on Erlang, as do large chunks of our telecomms infrastructure. It has an enormous number of users. What it doesn't have is an enormous number of developers. One of the good things about the Erlang (and Elixir) ecosystem is that there are a relatively small number of people implementing the bits you care about, and they all seem to be extremely competent engineers. The pieces are designed well, they are reliable and they fit together. They also have good abstractions so if you use good pieces then you get good results (e.g. with Phoenix you'd have a hard time creating a XSRF or SQL injection problem).
PHP has a bit of a perfect storm of problems - it is so accessible that anyone can and did use it. This meant a lot of people implemented things using it, with varying levels of competence. This means a lot of problematic implementation of a lot of pieces, built on a language and framework that didn't really try to prevent security problems and so didn't really have the tools to do so. In contrast to Erlang/Elixir above, you can take a set of tools in PHP and easily implement a very insecure website.
I guess where they're similar is that an error is generally going to only affect that one request, the next request will have a fresh handler.
(Of course, these are generalizations, you can always do things differently in either language).
It throws out the context baby with the state bathwater.