I've read that 그대 is a 'poetic' way of meaning 'you' - i.e. referring to the person you're speaking to.
I saw an example sentence:
앉으나 서나 그대 생각을 해요
Where it seems to be 'loving' in tone.
However, on the one or two occasions I actually heard it, it was used by a boss talking to a younger employee - so (probably?) not 'romantically' loving.
What are the different ways that 그대 can be used?