When scanning CPAN in that "Surely there's a better way" mode, I use some heuristics (read:prejudices) which roughly sort modules into the good, the bad and the kooky.

I'll search in the problem area, pop tabs for each module, then kill tabs based on the feeling I get from the docs. I'm talking about modules that do address your problem, but in such a poor way that you're better off without them.

I'm interested other peoples red-flags during this initial appraisal. Obviously, they're not absolute and will vary according to the general problem and specific context.
Update: The answers so far have largely been too sensible and rational. Express your inner bigot.

To start out, here's some I've managed to untangle from that "blargh" reaction.
Red Flags:

• Any of the usual code red-flags which are noticable from the module's docs: it reinvents wheels, uses globals, magic numbers, ... These have been done elsewhere.
• Massive, nested structures passed into new().
• It's callbackwards. Requiring an entire callback architecture when a few more methods would do.
• It parses pseudo-perl data structures or expressions.
• big_procedure_names_containing_pseudo_arguments