I miss writing concise stuff like:
$arr = array('a'=>1, 'b'=>2);
or:
foreach( $a as $k=>$v )

I don't like casting stuff all the time, or having to create specially-typed collections. Or having to check for null references or non-existent keys or undefined variables, which could otherwise be handled just fine as "empty" values.

I hate looking through a dozen class definitions to figure out what sort of specialized iterator I need to walk through the values of a collection.

I hate having to compile sources into binaries. I hate the extra time it takes to find out where a runtime error occurred.

I hate having to set up exception handlers, which once again means looking up more objects in bloated MSDN docs. I hate wasting time thinking about whether a method should throw an exception or return a status value.

Anyway, yeah, not so excited about C# anymore. It's pretty much just Java all over again.