How Important Are Manners In Your Home?

I was thinking about how often I remind my children to "mind their manners." I have always tried to instill manners ever since they were young. Saying "please," and "thank you." I have noticed when working with a lot of youth, that many do not have any manners. I think this is because many adults don't use their manners, or press the issue with their children. Am I wrong? Does anyone else see this as well? Let me know what you think!! Look forward to hearing your views.