You can wear a tshirt and yet look professional. I think OP used the wrong example. The worst case I think is not wearing shoes while not taking care of your na

You can wear a tshirt and yet look professional. I think OP used the wrong example. The worst case I think is not wearing shoes while not taking care of your nails. That is disgusting. The second worst would be not attempting to brush your hair or teeth after getting out of bed. The third would be not taking showers at a frequency high enough to overcome your personal natural tendencies to actually, physically, smell badly.