interesting !! by the way, 团建 you couldn’t find this in your English-Chinese dictionaries. maybe because it is not a word strictly，it's like english acronym, due to pronounce the word "团队建设" feel a little verbose, so generally always say "团建". like the same reason, there is another word "不明觉厉" is generated from "虽然不明白为什么但是觉得很厉害"。

Thanks for writing this! Request for clarification -- the acronyms with numbers in them, do people say those in english or chinese? 3C for example, is that "san1 see" or "three see"

Great point. 3C is san1 xi1/san1 sei1 (depending on dialect). I added notes for 2B, 2C and 3C. B2B2C also uses the English pronunciation of "to."