When you get so interested in a subject/field to the point where you eventually start looking at every aspect of life through that perspective.
Friend: ''Hey, what ya looking at?''
Architecture Student: ''Oh, nothing, just appreciating the intricate design of the doors of the building''
Sociology Student: ''Yeah, I wonder how many social exchanges have occurred around those doors''
Philosophy Student: ''But how and when do we consider something a door?''
Friend: *Sigh* ''Student eyes?''
Students: ''Yeah...''