@PeachRooibos: Interesting question. DH and I have been together for over a decade and our communiation has drastically improved in the past 3-4 years. I would say mostly because we are rather upfront with each other and are not afraid of what the other will think/how they will respond.
In terms of habits that get annoying, I must say, that I began to truly understand and love my DH more when I simply accepted him for who he was and recognized that I cannot/should not want to change him. Of course we will grow and change together, but I married a man I love, for who he is, not what I want him to become.
What I mean by this, is that I used to really encourage (borderline harrass) him to exercise more, eat healthier vegetables, clean things the way I did, ya da, ya da, ya da. It actually caused a lot of strain in our relationship because he felt like I was pressuring and nagging him. Of course I want him to be healthy, but he has to make the decision on his own and then I can support him. Suprisingly, I stopped all the nagging about 2 years ago, and I saw a change sortly after. DH, on his own, began wanting to try healthier foods. He randomly started eating his version of salads (i.e., lettuce, cheese and crutons) out of no where, he stopped wanting fried foods and he had the idea to start buying local, grassfed meats.
I was in shock! I literally bugged him for years to change his habits, yet, when I stopped saying things, he wanted to make changes on his own. And guess what, those habits have continued because he wanted it.
Basically, I have learned to focus on real problems (if we disagree on serious issues) and let less important ones go. You can’t change someone if they don’t want to change.
Now if something is really getting to one of us, we talk about it. We are always open to discussions, but that does not necessarily mean that action is always taken or a drastic change occurs. It’s hard to explain and it may not make complete sense, but it has worked really well for us.