From a definition standpoint, I describe manners as a compilation of rules and etiquette norms. Some are more obviously useful than others. Most table-centered manners can be traced back to simple hygienic roots. For example, putting your feet on the table will sprinkle the dirt and grime from the street floors onto the chicken pot pie. And others, like never wearing brown shoes with a blue suit, are more based on taste.
In a way, observing certain manners is all a show, a way to uphold an image, yet I wouldn’t put it on the level of peacocking or “Korean pretty boys” as Jason commented about my ‘importance of dressing nicely’ essay. To me, manners are a behavioral rather than visual aspect of upholding an image. Having manners differs from having an outward fashion sense in that the main principle of manners is not to show yourself off, but rather to add to the comfort of those around you. You open doors and pull out chairs for your date. You don’t bring up uncomfortable subjects at the dinner table. You avoid laughing at a funeral and don’t talk in a movie theater.
I personally get giddy when a guy opens the door for me. It’s not like I wouldn’t be able to do it myself, (knowing me, I’d probably run straight into it before I did) but in the most subtle way, the act shows that he’s attentive to you and is looking after your comfort. That, I believe, is the basic description of the effect of most manners. The lack of them is not necessarily detrimental, but following them makes the receiver feel appreciated and can also score major points for the doer. So boys, take note. With every door you open and every chair you pull out for her, your chances of getting laid increase by that much.
My main example comes from a dating perspective, but we can see the benefit of the application of manners in many aspects of life, such as school, work, and among friends. You don’t talk over your professor in the middle of lecture, you say 'Excuse me' when you bump into someone in the hall, you’re on time to scheduled meetings, and you cover your friend’s movie ticket if he or she forgot cash at home. And, as an extreme example, you’re generally courteous with your girlfriend’s parents. Why? Because you want them to like you and to accept you and be comfortable around you.
If you want people to view you a certain way, being courteous to them is a way of showing them that you’re worth the effort and that you care what they think of you. It’s a very direct and personal way of shaping your image in other people’s eyes; much more powerful than the clothing you wear or the car you drive.
But in that case, if you aren’t courteous, does that make you a disrespectful person? Not necessarily. However, someone who follows the rules of etiquette will end up reaping the potential benefits of following the basics and end up with an advantage in his or her social circles simply because he or she will be seen in a different light by those around him or her.