When typing (car ''abracadabra), the interpreter will transform the expression
into: (car (quote (quote abracadabra))), then it will evaluate.
First the symbol car becomes the car procedure, then quote gets evaluated as a
special form, which means the surrounded expression should be left
unevaluated, so we get something like: (#<car:procedure> (quote abracadabra)),
now car gets applied, and we get the expected result.