The "hard" languages are ASP.NET, C++, C#, Haskell, Lisp, and Objective-C.

Here's a breakdown of the languages with the number of positive/negative suggestions (popular was assumed to be a good thing):

ASP.NET : +1 -3 = -2

C++ : +1 -2 = -1

C# : +2 -1 = +1

COBOL : +0 -1 = -1

Erlang : +1 -1 = +0

FORTRAN : +2 -0 = +2

Haskell : +2 -2 = +0

Java : +2 -2 = +0

JS : +2 -2 = +0

Lisp : +3 -1 = +2

Obj-C : +0 -4 = -4

Perl : +0 -2 = -2

PHP : +1 -3 = -2

Python : +1 -2 = -1

Ruby : +2 -1 = +1

Smalltalk: +1 -0 = +1

VB.NET : +1 -1 = +0

By this metric, Objective-C is the worst language, twice as bad as PHP (oh my!), and Lisp and FORTRAN are the best languages.