  Physicality has the bad habit of sneaking up on unsuspecting physicists.
Unfortunately, it comes in multitudinous incarnations, which will not always
make sense in a given situation. Breaching a warp drive metric with physical
arguments is all good, but often what counts as physicality here is but a mere
mask for something else. In times of analogue space-times and quantum effects,
a more open mind is needed. Not only to avoid using a concept of physicality
out of its natural habitat, but also to find useful toy models for our enlarged
phenomenology of physics with metrics. This journey is bound to be as vexing,
confusing, and subtle as it (hopefully) will be illuminating, entertaining, and
thought-provoking.
