You see, I have no problem wearing one, it's the right thing to do and doesn't do any harm, but I'm not so convinced it helps so much.
Now, I only recently understood properly why wearing a mask if you are not infected does not help you, only if you are infected does it help you stop passing it on.
If you are wearing a mask and an infected person sneezes/coughs close to you, even though you are wearing a mask, the virus can enter your body through your eyes. If the infected person is wearing a mask and coughs/sneezes near you, then this should prevent, or greatly lessen, the opportunity of you getting infected. Since nobody really knows if they are infected or not, unless they have recently tested positive, then everyone should wear a mask. You should also wear goggles to be on the safe side though.