My main problem with Perl is references and contexts. Most of the experienced programmers I work with find themselves unable to write or debug code that requires the use of these Perl concepts.

For example, my co-workers and I find it easy and intuitive to work with lists in Python

    xs = [5, 6]
    xs.append(7)
    print xs[2]     # prints 7
    xs.append([])   # easy to append lists to other lists
    xs[3].append(6) # easy to append to the inner list
    some_func(12, "hello", xs, True) # easy to pass to a function

In Perl this would be way more complicated for reasons that are obvious to someone who knows Perl well, but a mystery to people who use Perl casually.

    $xs = [5, 6];       # must be a reference
    push @$xs, 7        # deference $xs as a list
    print "$xs->[2]\n"  # still not too bad
    push @$xs, []       # add a nested list reference
    push @{$xs->[3]}, 6 # omgwtf?!
    some_func(12, "hello", $xs, 1) # not too bad

Understanding "push @{$xs->[3]}, 6" is asking a lot just to deal with a nested list that you need to pass to a function, especially compared to the easily understandable "xs[3].append(6)". For that matter, it's asking a lot to make you understand the difference between a list and a list reference. It's asking a lot to ask to understand the concept of "evaluating in a ___ context", especially when other languages manage to do the same things without these concepts.