I've been geocaching since 2013 but only on occasion — 85 finds at present — so I'm not new to it but I'm not very accomplished. Last week I logged a Needs Maintenance for a log that seemed to be full. I can't swear that I wasn't mistaken. I didn't expect it to be controversial, so I didn't make a photographic record or anything, but we'd flipped through it looking for empty space and ended up halfway down the last page. The cache owner, I just noticed, posted a breathtakingly snide note back saying that the log could not be full, and belittling my relatively low find count ("Someone with 81 finds since joining in 2013 shouldn’t be putting a needs maintenance" etc., etc.).
Did I violate common etiquette here? Best I've been able to figure from searching the forums is that some people take it personally, and other people think that Needs Maintenance just means needs maintenance. I thought I was being helpful. If I'd ever gotten around to placing any of the caches I've thought of, I would certainly want to know when the log needed replacing or anything else needed attention so I could fix it.
(To head off one possible response, I know now I could have notified the owner privately. I'm not sure I was aware of it before, but even if I was, it didn't occur to me because I thought this was exactly what Needs Maintenance was for.)