Agree that some masks are problematic. Was wearing mine for maybe 35 minutes straight the other day, in line outside at a supermarket and then inside. By the time I got to the register I couldn’t stand it. My body was breathing deeply and rapidly, I think to get more oxygen. Basic cloth mask. Thank goodness I don’t have to wear one all the time. (*I suspect a mask that would give me less problems would also be one that had better air exchange - meaning more risk of receiving or transmitting aerosol particles).