For me the biggest pain point was the lack of great libraries for doing basic stuff like HTTP requests (client side). I was not able to reach the performance of

For me the biggest pain point was the lack of great libraries for doing basic stuff like HTTP requests (client side). I was not able to reach the performance of Java/JVM with the Erlang implementation and I could not figure out what I am doing wrong. OTP and those pattern associated with it are still a bit opaque after reading countless manuals, howtos and books.