I know, strange question... My friend wishes to know which yoga pants color is more casual: blue, black, or grey? To be honest, I do not know! I am a male; nonetheless, for some reason she wants a guys perspective. And how should I know which color is more casual, I thought yoga pants were... Yoga pants, but she wants to look casual. Thus, back to my question which color would you consider more casual from blue, black, or grey? Please help.