What a bizarre thread. I don't personally care what title people choose to assign to me, as long as it isn't "You fool". In my profession most women retain their maiden name if that is what they went on the solicitors' roll under. We are also exclusively known as "Miss". I have only heard one lawyer being addressed as "Mrs" in court and she was slightly eccentric and notorious for having made an almighty fuss about this exact isse. Everyone scrupulously referred to her as "Mrs" with a snigger from then onwards.
I am not married. I get addressed as Ms Panda, Miss Panda, Mrs Panda, Miss DP, Mrs DP, Miss mis-spelled Panda, Mrs mis-spelled DP, the whole range. I also have a different name to my son who has DP's name. I can honestly say it does not trouble me in the slightest. I am surprised at people getting annoyed at midwives or teachers using a generic, catch-all term designed to prevent offence. They are not making any judgement about the relative importance of your marital status in the world at large, or to you personally - they are just imparting information as quickly and neutrally as possible.
I don't think marriage is anything to be particularly proud of. The relationship is what you should be proud of - married is just what it is called. It's not better than being partners, civil partners, common-law partners, whatever you choose to call it - it's just one of a range of ways to live your life.
If the status of being in a marriage is important to you in itself then that is nice for you, but by taking offence at some stranger failing to confer that status upon you I am afraid you do suggest that you think being married gives your relationship a higher standing than that of those who are not married. By getting all "ooh look at the defensive unmarried women" you rather reinforce it.
Be proud of anything you like, be happy to be married, but why insist that every passing stranger celebrates that with you every minute of your life?