You will exchange hellos and chats with people you know but not perfect strangers. So why do some dogs feel the need to do this, mine does for sure, he thinks it’s perfectly acceptable that he should meet every dog and get the opportunity to play with them - or does he? I look back and I imagine a world where I’d put all my effort into teaching Elvis that if we meet another dog then we just walk on by calmly, or at the very most, if it’s unavoidable, we meet have a quick bum sniff and move on. Would he have then forgotten how to be a dog and just stood staring at them hopelessly if he had been taught to mostly pass other dogs calmly instead, I don’t think so. It’s if buts and maybes but what dogs that struggle with dog to dog interactions lack is usually the ability to disengage and ‘socialising’ them with every dog they see won’t help that it will make it worse. So that’s why I’d prefer it if on lead greetings just weren’t a thing amongst dog owners, unless it’s an arranged meet between pals. When dogs meet on lead they are contained by us, mostly unable to behave how they would naturally, we break their behaviour chains for them.