I get tired of being told that standing with my arms crossed shows a bad attitude, it's closed off, antagonistic blah blah blah.

Bollocks. I stand like that not because subconsciously I don't want people to approach me, but because it is comfortable. Clearly whoever came up with the 'hidden meaning' behind this posture has never had to lug around a large chest 24/7. Tugging my arms under my boobs gives them a bit of extra support that takes weight of my shoulders and back. I wear good fitted supportive bras that give me great shape but I still end up hunching over to compensate the weight so if I want to stand with my arms crossed to give my shoulders a break I DAMN WELL WILL.