One of my little guilty pleasures is checking the comments on the most innoquous tweets, and look for the angriest replies. One of my favorites was an angry reply at a post-WW2 partition-proposal for not matching current reality.
Political maps may be the best for this, because they are usually so verifiable and also - usually - purely informative, wether a country shown is Norway or Italy is really not a matter of debate, nor a matter of emotional leanings - wether or not the borders are current or former, are likewisely not going to be a matter of personal taste or offense.
Concerning maps, some favorites are getting angry at for example a historical map being "Euro-centric" if it's a map of Europe, and also - if it's a map of Europe, there's bound to be some empassioned outbursts regarding the exact definition of Europe.
More precise wording may unruffle some of these feathers, for example instead of saying simply "Topographic map of Europe" say "Topographic map of Europe, but also including Russia and Turkey, with some portions of the southern Caucasus (oh and not ALL of Russia is included, since large parts of Russia count as Asia!!!) also parts of Syria, Lebanon, Israel, also the northern tip of Morocco is kind of included, Algeria and Tunisia may be visible, as well as the westernmost edge of Kazakhstan, jesus christ - did we miss something!? Please, dear GOD did we miss something!?!?!? Also - are oceans to be countes as Europe? Like, the Mediterranean!? CAN WATER BE PART OF A CONTINENT!? If they are not - then the HUMBLEST of apologies may be in order!!!"