If a dog is stressed or afraid, their demeanor and typical behaviors will change. If you see this in your dog (or really any dog you know) you should step back and check on your dog. Are they hurt? Did a new dog come around they don’t know? Has the weather changed? Is it hot outside? When was the last time they had a chance to go outside to pee or poop?
Dogs with poor social skills oftentimes just don’t know better. They will bounce off of everything, jump on everyone, run around like crazy, and investigate everything they can get their paws, snout, and eyes on! These dogs can come from any background, whether a rescue or puppy from a great breeder; if they haven’t had experience in new places and new situations, this can be how they respond.
Also, it's your job to never let anyone else allow your puppy to jump up on them! They will say, "It's OK, she's just a puppy, I don't mind if she jumps on me". You must rush in and pull the puppy down immediately, put your pup in a sit, praise the puppy then scold the person ! Continue to hold the puppy in a sit and let the person greet the pup. Explain to them they can never allow the puppy to jump on them - the puppy must sit to be greeted. To stop the jumping up behavior in pups, I do as much people training as puppy training!
For pups that ambush you and bite your rear end while playing outside, hide a toy or two in the backyard and ask them to find the toy. Bad weather can give puppies cabin fever when they don’t have adequate time outside to run off the energy. Mental stimulation can wear them out, too. Show your puppy a favorite toy and then roll it up inside an old towel and knot it to make a puzzle. Encourage the pup to unravel and get the toy. You can even tie the first toy-in-the-towel inside a second one for more of a challenge to relieve boredom.
When he gives up and stands still (staring at you like you’ve gone crazy), THAT’s when you greet your dog and give him some love and attention. This is the reward he was looking for. Following these rules will ensure he learns that he will only earn that reward by not jumping (don’t overdo the high-pitched voice saying, “GOOD BOYYYYY” or it will just rile your dog up even more to start jumping again).
Dogs like and need consistency, so if you are not allowing your dog to jump on you, everyone in the family and everyone who greets the dog must do the same. You, as an owner, must make sure this happens. It will only confuse a dog if you allow them to jump on some people who say they do not mind, and tell him not to jump on others. Once you decide you do not wish your dog to jump on people you must apply this to everyone at all times unless you give the dog a command to jump. A dog should never jump on a human of its own free will.