A poor habit I see in too many weight rooms is the propensity to crank back the neck and look up at the sky when doing squats. I don’t how or where this started, but I think I know why. Due to a lack of mobility and/or stability many people lack the ability to maintain a neutral spine as they get lower in the squat and will begin to tuck under their pelvis and flex their lumber spine. By tilting their head back it creates extension in the cervical spine which will reflexively cause the body to want to extend their lumbar spine simultaneously, something sometimes referred to as the Lovett Brother Reaction or Relationship. This gives the false illusion of maintaining neutral and fighting flexion.
Unfortunately, even though your spine and hips are intimately related, you can’t replace one with the other and ultimately this going to lead to unwanted hinging at the lumbar spine and SI Joint, as well as increased shearing force at the spine at both the neck and low back.