I just want to enjoy walking my dog. Breezey is two this summer. We've done obedience classes and are now doing agility classes. She loves to learn and almost drags me into the building

She can work off leash and closely around other dogs. The first few agility classes I really concentrated on her focusing on me and me only. She can sit and watch other dogs run a sequence with no problem. She did very well at obedience classes. One woman (who was in beginnger class with me) commented on how much she has improved since she first came.
Now when I take her around my neighbourhood, she is embarassing. Barking and lunging at every dog she sees. The behaviourist showed me how to click when she looked at something scary (kids, bikes, snowblowers, fast cars). When I clicked, she'd look back at me and I treated.
She is doing better with kids running around (I give her lots of space, she looks and I c/t. I thought we were progressing with other dogs out but she just seems to be regressing. The other dog doesn't even have to look at her or bark (and they are across the street). She focuses right on them and starts barking and jumping toward them. A couple of times I got in front of her and backed her up a bit and blocked her view but I could see she was trying to see around me.
I walk with a group of dogs every other week or so and she's fine with them. I walk with my friend and her spaniel (he's pretty laid back) and she'll bark at other dogs.
THis dog just baffles me. I tried telling her sit, down, etc to get her to listen to me but she was only half listening and wanting to focus on the other dog.
I took her to visit a friend who has two dogs to practice my training and she was very well-behaved. We practiced heeling, focusing on me while her dogs were running around and I was quite pleased with her.
Do two year old dogs have a phase? I sure can't explain the Jekyll and Hyde dog I seem to have.