Improve "How to think in haskell?"

VL1.tex

@@ -244,6 +244,7 @@ Let's reiterate. Haskell is:
 \begin{frame}
 \frametitle{How to think haskell?}
 \begin{itemize}[<+->]
+\item forget about imperative, procedural, OOP; forget about any programming language
 \item think in types!
 \begin{itemize}[<+->]
 \item don't be afraid of type errors