Our inconsistency perpetuates the problem. Some of the time we tolerate the jumping and ignore it. Other times we reward the behavior by exchanging enthusiastic greetings. But when we're dressed up and the puppy's paws are muddy, it's a different story. Reprimanding the puppy for jumping up usually does not work. Either the puppy misunderstands the reprimand as praise or he gets even more excited and the jumping gets worse. If the reprimand is severe enough, the puppy may stop jumping at that moment but it doesn't solve the problem altogether; and it certainly is not a very nice thing to do. It's very similar to a person approaching you with a big smile, arm extended to exchange a hand-shake and you bopping the person in the nose. Even if your puppy learns that jumping up on you is not a good idea, he will usually get away with jumping up on everyone else.
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?
Homecomings and departures are a prime time for jumping up because puppies want to greet you or stop you from leaving. Turning your back on some of these dogs revs them up even more, so instead, try ignoring the bad behavior. “Ignore” means you make no eye contact, say nothing and stand still like a zombie offering no reaction to silly puppy behavior.
Start by teaching your puppy the word NO. Use that word only when she is doing something you do not like. You have to use the word NO in a loud, stern voice that is different from all other ways you communicate with her, so that she knows there is something wrong. You also have to catch her in the act that you don't like, so that it will associate the word NO with the action that she is doing. Be consistent, and follow your verbal command with a light smack or moving her to a time out spot.
When a dog jumps on a human of its own free will, it is not "greeting" the human, it is asserting its dominance over the human; it is the dog communicating that it is alpha and/or wishes to own/control the human. A subordinate would never dream of running over and jumping on the alpha dog of the pack. Space is respect and lower members of the pack respect the higher members. If your dog jumps on humans, it does not respect them. Note: when a young puppy jumps on humans it is sometimes its attempt to reach one's face. Puppies need to be taught not to jump up on humans as this behavior will manifest into other meanings as the puppy grows up into an adult dog.