I felt terrible each time I didn't recognise a language I'd used. Makefiles, Delphi and Batch files, to name three.
What is interesting is so many languages look like C or Lisp or ML or its variants.
I missed Erlang, even though I have a copy of Programming Erlang somewhere. Guess it didn't take.
The other one where this happened was F#. I tried OCaml and Snandard ML and was thinking "this HAS to be OCaml..." and again, felt silly for not thinking of F#.
Boy am I smart.