  In recent years, observations have uncovered a population of massive galaxies
that are invisible or very faint in deep optical/near-infrared (near-IR)
surveys but brighter at longer wavelengths. However, the nature of these
optically dark or faint galaxies (OFGs; one of several names given to these
objects) is highly uncertain. In this work, we investigate the drivers of dust
attenuation in the JWST era. In particular, we study the role of stellar mass,
size, and orientation in obscuring star-forming galaxies (SFGs) at $3 < z <
7.5$, focusing on the question of why OFGs and similar galaxies are so faint at
optical/near-IR wavelengths. We find that stellar mass is the primary proxy for
dust attenuation, among the properties studied. Effective radius and axis ratio
do not show a clear link with dust attenuation, with the effect of orientation
being close to random. However, there is a subset of highly dust attenuated
($A_V > 1$, typically) SFGs, of which OFGs are a specific case. For this
subset, we find that the key distinctive feature is their compact size (for
massive systems with $\log (M_{*}/M_{\odot}) > 10$); OFGs exhibit a 30% smaller
effective radius than the average SFG at the same stellar mass and redshift. On
the contrary, OFGs do not exhibit a preference for low axis ratios (i.e.,
edge-on disks). The results in this work show that stellar mass is the primary
proxy for dust attenuation and compact stellar light profiles behind the thick
dust columns obscuring typical massive SFGs.
