There is so much baggage - religious baggage - associated with the word "angel" that it's hard to separate that from what teachers and guides have said.
My own viewpoint is that angels are distinct entities but often with (perceived) forms that resemble what we BELIEVE they look like. So they might be perceived as bright and/or glowing individuals, kinda our size overall (or perhaps bigger and more impressive) and often having wings. That's kinda what we're taught as kids by various religions or for that matter, still taught when adults! It doesn't matter at all to me and it's rare I even think of angels let alone want to see one - hence I might be the most unlikely to!
As for the notion of "guardian angel" I do think we have a "guardian spirit" who tries to help where it's 'allowed' and where it's possible. Some individuals appear to be aware of - or actually do see - their own and may even interact with them. I accept what these guys tell us but I'm less accepting of some of the stuff I've heard about their angels' (assumed) roles. I DO think we each have a guardian spirit but I also think many misunderstand her/his role.
What seems plain and unambiguous is that assuming angels are kosher there's no certainty we'll ever see our own but a fair certainty most of us will be unable to interact with it/her/him at a conscious level.
