I am a useful idiot, i take public transportation, i am.constantly in confined spaces with people who have poor hygiene, and have no idea how much germs they are transmitting whrn they cough in someone face, or when they spit,or dig in their noses,nor do they care.
Those are the "normal" people, we have so many homeless, or drug addicted people on said trains and sometimes buses, spreading their body fluids everywhere and also coughing and spitting and throwing up.
No a mask by ITSELF will not totally protect you, it is a helpful barrier.
if one does not like it, or thinks because studies say it does not protect you 100% then it is useless,very good, i hope you keep the same energy with Condoms, Seatbelts, Helmets, and all other safety devices.
I genuinely feel sorry for people with compromised immune systems who have no choice but to wear a mask because contracting even a common cold is very much a life anf death thing.
On the good side they do not have to worry about inconsiderate people calling them idiots when trying to stay alive and live a normal enough life is paramount.