Too many dogs running loose with owners reassuring me that they're friendly, just want to play, etc. I don't give a fuck, keep them away from my dog unless I say it's OK.
Exactly this penny dropped when my owner training kicked in last weekend - why should my dog and I be put through stress because of other peoples' idea that dogs should be just left to 'socialise' without any control. We wouldn't do this with our children!
Suddenly I'm very forthright if I want someone's wandering dog to be controlled, and it's liberating.