I should imagine it seems vague to you because you don't trouble yourself much over it. It seems quite straightforward to me,.
There are people of a reductionist, eliminative materialist, empiricist bent with a limited range of things which have meaning then there are those who think there's a bit more and/ or that it's a bit more complicated with ideas and abstracts and experiences and feelings, and greatness and the numinous and that because it isn't described adequately by those isms, it's referred to as the spiritual a term which has different meanings in different contexts.
What an incredibly patronising post Vlad.
The notion of spirituality doesn't just appear vague because I don't recognise the things you mention - nope it appear vague because its definition is a wide or as narrow as people choose it to be (typically for their own purposes).
I assure you that I am as capable of feeling as inspired by nature, as emotional by listening to or singing music, as moved by love etc etc as the next person. The difference isn't how powerfully we feel these emotions, but whether we badge them with the (poorly defined) term 'spiritual'. You may do, I don't - but that doesn't make me 'shallow' or unfeeling or uninterested, merely not prepared to slap an ill-defined 'sticker' on things that rather transcend such pigeon-holing. Still less do I wish to allow those such as yourself to try to subvert such power and emotion into a petty 'hey, look, god' argument.
Oh and by the way, the emotions we feel are increasingly understandable through neurophysiology. Does that make them less important to the human condition? Not a bit.