You may think that I am a bit crazy, but every single time that I carry more than one lens with me (and I like doing that, since changing lenses is part of the fun :-) ) I cannot avoid to wonder if it's better (as in "safest") to place the unmounted lenses top or bottom up in the camera bag.
So, what do you suggest? What's worse for a lens, receiving an eventual bump/shock on the glass side or on the body side? Or: how do you choose which side they go?
Obviously I am not thinking about dropping the bag/backpack from some height, but to the normal kind of stresses to which a bag is exposed day-to-day.
ps: I have added some layers of bubble wrap to pad the bag (and backpack) but my obsessive self is still not happy, even if I am rationally aware that the difference, if it exists at all, must be very small.
pps: bonus points for answers covering other equipment, like flashes, etc...