Every LATEX user faces the “compatibility nightmare”one day. With so much intercession capabilitiesat hand (LATEX code being able to redefine itself at will), a time comes inevitably when thecompilation of a document fails, due to a class/styleconflict. In an ideal world, class/style conflictsshould only be a concern for package maintainers,not end-users of LATEX. Unfortunately, the world isreal, not ideal, and end-user document compilationdoes break. As both a class/style maintainer and a documentauthor, I tried several times to come up withsome general principles or a systematic approach tohandling class/style cross-compatibility in a smoothand gentle manner, but I ultimately failed. Instead,one Monday morning, I woke up with this vision ofthe LATEX biotope, an emergent phenomenon whoseglobal behavior cannot be comprehended, becauseit is in fact the result of a myriad of “macro”-interactions between small entities, themselves inperpetual evolution.