...just never with your mouth open if birds are around!!!
In London especially it's easy to get lost in the whirl of that sheep like, robotic commute to work - always in a hurry to get nowhere fast, walk along with your elbows out and grunt and snarl at anyone that looks your way. Your head down and your London march at the ready and hurry hurry hurry until you get to your chosen location.
I hate how people end up so impolite and lost in their own world that they have no spacial awareness of anything at all and worst of all - especially in London when it's such a pretty city - they forget to look up!
Always remember to look up!!!