I am a dog owner. I get irritated when I see piles of doo poo sitting on the paths (and yes I do pick them all up, whether from my own dogs or not). I also get irritated when I see discarded fast food cartons, beer cans, plastic bottles littering the woods (and yes, I pick those up too).
Here we have segregated areas. There are areas where all dogs are banned, areas where dogs are allowed on a leash only, areas where dogs are allowed providing they are under control (so off leash is allowed but with excellent recall and within sight at all times, otherwise on leash only) and areas where dogs are allowed off leash. There are enough of all of them that everyone's needs can be catered to - the local beach has two halves, one is an off leash exercise area and one is a dogs banned area. The local parks are dogs on leash only areas, the national parks are dogs banned areas. Playgrounds are dogs banned areas, large expanses of grass next to playgrounds are off leash exercise areas. It all works.
You still get inconsiderate owners and dangerous dogs. You still get dogs that escape from their gardens and attack other dogs (my friend had to go through that, thousands of dollars on surgery and vet bills) but on the whole, the rules are observed well and everyone has somewhere they can go.
I disagree that dogs need off leash exercise areas though. It's much easier for me to exercise my dogs off leash, I can saunter slowly along throwing tennis balls while they run around and get lots of exercise. However - it may be more hassle for me, but I can also go for really long hikes with them on a leash and they will still get lots of exercise - anyone that can't guarantee their dog will be sufficiently exercised if they're forced to stay on leash shouldn't be owning them.
If a dog jumps up at you, don't lift your arms (they'll try and jump higher, thinking it's a game). Hands down in front of you with palm flat, firm "No", lift knee up of whichever side they're jumping towards (or straight in front, use whichever knee will keep you most stable while standing on the other leg!) to block them. Turning your back will present a "boring" part of you and they won't jump so readily.