Leniency in journals' paper structure "guidelines" (required sections and divisions)
I hate it when a journal decides to stretch you on a Procrustean bed of arbitrary structure, since many research projects simply do not fit on such.  Some really want you to fit their arbitrary structure, while others will bend, and it's not really possible to know which is which and how much flexibility you've for unless you talk to an editor.

That said, I've often found that with a little bit of mental gymnastics in how you approach "results and discussion" you can generally make things work.  Consider, for example, this decently-cited paper of mine, which didn't really fit the "intro - results - discussion - methods" format desired by the journal, since it was about a (fairly complex) method.  Well, if you think of the method as being the result, then we essentially shove the whole paper as we wanted to structure it into the "results &amp; discussion" section, with our preferred structure as subsections.  The "methods" section then contains all of the boring details about protocols for the validation tests that we ran.

Bottom line: often a journal really means it about its structure requirements, but that actually constrains you less than you might think.