On Photons and Light

I’m puzzled.  It is night and when I go outside I can look in a window and see what is happening inside. This means photons are passing through the glass.  When I come back inside and look out the window I can not only see outside but I see a reflection of myself indicating that not all of the inside light is going out.  Some of the photons are bouncing back into the room.  I am wondering why?  Is it random or is there a difference in the photons that pass through glass from the photons that bounce back.  Not being a physicist I don’t know.  I was just wondering. 
But it did make me reflect (pun intended) on some of my students who seem to let little light pass through their foreheads.  I lot of it seems to bounce back.   Lest I sound overly negative I happily say most of the light goes into most of my students and if it doesn’t I try again and again.   Good pedagogical process tells us students need to hear something three times for them to remember it.  So I often repeat myself.
All which brings us to God striving to get us to understand how much He loves us, how much He wants us to rejoice in His immense mercy, how much He wants us to allow His Spirit to move inside to motivate and strengthen us to be like Jesus, how much He wants to use us to further the cause of a better world, how much He wants to return to being sin to its ultimate end.
My high school English teacher would think little light went through my forehead because of the above “run-on sentence.”  Diagram that one!