Swearing. I live in South East Asia, where swearing is taboo. Visiting my homeland of the UK, it takes a few days to get back my expletive laden fluency. The first few days are painful, as everyone thinks I'm being pretentiously posh. Upon returning to Asia, typically i offend a few people until my language is restrained. Sadly, Southeast Asians don't appreciate how expressive, cathartic and fun swearing is, it's a fucking shame.