By that logic you can't observe anything or explain anything, though. All the force carrying bosons (like the photon) have to interact with fermions (the electr

By that logic you can't observe anything or explain anything, though. All the force carrying bosons (like the photon) have to interact with fermions (the electrons and quarks that make up your equipment and your body). Some of the interactions happen due to on-shell photons ("light") but most happen due to completely off-shell photons (EM force). They are really the same interaction. Don't get hung up on the "virtual" in the lingo about particles. All particles are more or less "virtual" depending on how you analyze the problem. I'm sorry there is not a more intuitive explanation of this.. The underlying QFT building blocks are so far from classical physics. Even concepts like energy and momentum are in some sense emergent properties that lose most of their classical intuition "at the bottom", this is reflected by the Heisenberg uncertainty relationship for example.