I must admit that I've caught myself doing exactly that just recently and been mortified. Living alone, I don't feel the need when yawning at home as others have pointed out but it's a slippery slope so I'm reverting to behaving as though there were someone with me all the time.
No, no to putting a hand to mouth when coughing or sneezing. Like the Americans, into the elbow. You don't know who's hand you may have to shake or which door handle you may have to use before you get a chance to wash!
I hate seeing feet on seats and am always admonishing my DD for sitting with her feet on the kneeler in church. They're for knees not outdoor shoes!
Incidentally, someone told me recently that yawning is neither a sign of tiredness or boredom, it's a sign of too little oxygen in the brain and that is why it's so catching. Apparently, your brain sees it as a message that there's a shortage of oxygen so makes you yawn to pull more in.
Not sure of the truth in that mind you, anyone else?
Estranged Son and Future Granddaughter
To think that London, or anywhere else for that matter, does not belong to any one demographic