Why do we need to ask? Aren’t our Guides psychic??

I’ve often heard that one’s guide or angel can’t help unless asked yet… I’ve wondered why this is the case.  I mean, I’m sure they see and know what the issue is and the solution.  They have the big picture view and endless resources.  They surely don’t like to see one struggling.  So then why does one need to ask (in the first place) and then be so specific when asking?