It's well established that creationism has no place here. I completely agree, but I came across a question which, so far as I can tell, is asking for examples of situations where evolution is an unlikely explanation. The question seems quite popular, which is surprising given its lack of clarity and the fact that it's asking for a list of things that don't exist. Should such questions be closed?
I've closed it as not constructive now, I remember voting to close that question, but that was before I became a moderator and the close vote decayed as we didn't reach 5 votes.
The "most difficult to explain" is a very vague and subjective criterium, that question is just not a good fit for a Q&A site.