@mickeyroe Like everyone else here I immediately assumed you're a young woman, haha.
There's a bloke that goes to the same park as me with a GSD who's constantly mansplaining to me about dog training. I have a BC.
My BC was born a little nuts (strong instincts) so every walk is also a training session and I'm interacting with her throughout, but she's allowed to stop and watch things she's interested in so long as she stays calm. She stopped to watch this GSD playing ball. If I'd have clocked out was this guy's dog I would have moved her on but unfortunately I didn't and he came over.
"How are you?" he calls over and I shout back "good"! which is my dog's marker word so she snaps her focus to me and gives me eye contact. I laugh and give her chicken.
He says, "what is that, chicken?" I tell him it is. He says "yeah that's ok" as if giving me permission then calls my dog over.
At first she jumps to greet him and he pushes her bum down to make her sit. She won't, she's just confused, obviously, so I say "lie down" and she does it. He says "oh that's quite good" then immediately goes "right..." and launches into about ten minutes of unsolicited, almost entirely incorrect, advice on training
after I'd just demonstrated I know what I'm doing (and he doesn't). To be honest, I think he probably did that to try and get the "upper hand" again because I was clearly doing fine on my own.
Your neighbour is an insecure dickhead. Remember he's a little boy trying to impress you every time you see him and when you respond imagine you're patting him on the head and saying "there, there..."