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Sometimes, as I am walking, for example, in a long corridor, I will randomly make eye contact from across the corridor with someone I know personally who is walking in the opposite direction. I want to greet this person but I am always unsure on how to do it. It's always a bit awkward because of the initial distance which prevents vocal greetings, but waving from afar and then slowly walking towards each other followed by another greeting is also kinda weird.
So my question is :
What is the best way to behave when you see someone you want to greet but they are far away?
Sometimes I just wait to be close enough to greet vocally but the long walk without acknowledging each other is still weird.