Add difficulties section

VL1.tex

@@ -597,6 +597,22 @@ Now that we know the basics, let's clear up some common misconceptions about has
 \onslide<+->
 You can!
 \end{frame}
+
+\begin{frame}
+\frametitle{Difficulties}
+Haskell is very powerful and can be used for pretty much anything. However, there are difficulties in any language. Let's name a few for haskell:
+\begin{itemize}[<+->]
+\item intellectual complexity? New way of thinking?
+\item although you rarely need it in haskell, debugging can be difficult at times
+\item because the type system is extremely powerful/complex, type error messages can be very confusing and don't always show the error you expected
+\item no premium-like IDE with every possible feature (yet)
+\item dynamic linking is sort of WIP yet, lots of ABI breakage
+\item because most of the world thinks in imperative style languages, it's often difficult to find pseudo-code for functional style languages, so you end up reverse-engineering algorithms
+\item some problems that are trivial in imperative languages, can be very difficult to solve in idiomatic haskell and vice versa
+\item practical cryptography is possible, but a difficult topic in haskell, see \url{https://mail.haskell.org/pipermail/haskell-cafe/2015-February/118059.html}
+\end{itemize}
+\end{frame}
+
 \begin{frame}
 \frametitle{Toolchain}
 You need: