Cruising, and travel in general, used to be an experience I looked forward to. Now, I find myself spending more time developing strategies to avoid those who just cannot seem to get along with others. Whether it's the saving of lounge chairs, rude behavior in the dining room, getting run over by strollers, or loud conversations in the passageway when most are asleep, I mourn the fact that our self-centered society has abandoned courtesy and respect. I can still enjoy cruising, but I find I'm spending more time on my balcony enjoying a cigar than mingling with the other passengers.
Oh, I don't think it's all that bad. Just when you think it's never going to stop raining, the sun comes out. And if it doesn't come out as quickly as you'd like, it's good for the garden. I focus on the positive and don't worry about the negative. To me, the glass is always half full, not half empty. For every bad thing or person in this world, there are many more good things or people.
I try to not let the actions of others bother me, since I like cruising so much. A bad day on the ship is frequently better than a good day on land. Rude people and actions are certainly not pleasant, but try to ignore then if you can.
It's almost impossible to stop people from being rude in crowded situations. The best defense is to avoid overly crowded ships. First, pick a ship with a high passenger to space ratio. This info can be found in www.mytravel.com. Then, get your TA to help you choose desirable times to cruise when the ship is likely to be the least crowded. We actually gave up cruising for a while because of the problems you mention. Now, we've found this method really works.