I usually keep this to myself, but hey, I'm feeling a little counterhegemonic.
If you are a woman in a heterosexual marriage who changes your name when you get married, I think a little less of you (as I do for the husbands who support/encourage/require such a change). Sorry, it's true. In the long run, it doesn't really matter, because you may have many other excellent qualities that will make up for the fact that you've chosen to do something I find to be incredibly stupid.
The reasons women give for changing their names are ... wow, I have to find different ways of saying "stupid" if I'm going to write this post.
1. "My husband's name is better/shorter/prettier/whatever than mine." Mm-hm. My friend whose last name was Stryjewski changed her name; her brother never changed his.
2. "Why shouldn't I take my husband's name? After all, right now I have my father's name." Well, that's between you and your parents. But the longer you have your name, the longer it becomes a part of your identity. When you parents gave you your father's name at birth, yeah, that would have been a great time for you to change it, if you could. But by the time you're 18 and can change your name, you've had your father's name for 18 years, and it's YOUR NAME. You've been interpellated, I guess. (Yeah, my Althusser is way rusty.)
3. "How will people know that I'm my children's mother if we don't have the same name?" Hm. Gee. I don't know. Every day when I go stand outside my kids' school to pick them up, I wear a sign saying "WIFE OF HUSBAND'SLASTNAME" so that my kids know whom to run to. Thank the FSM that they're old enough now to walk themselves home, because once I forgot the sign and my kids wandered around the schoolyard for hours, and Child Protective Services was called and it was A Thing.
Oh wait, that didn't happen.
When I call the school or the pedi or something, I say "Hello, this is Wendy MyLastName, Eric and Sophie Husband'sLastName's mother." If you have a common "easier" name (See #1) you probably have to say that anyway. Here in SE Mass, chances are if your name is Medeiros, for example, you will probably have to say "Hi, I'm Jane Medeiros, Ashley Medeiros' mother." As opposed to Jacob Medeiros', Samantha Medeiros', or Joey Medieros' mother.
The fact is that divorce is common, and plenty of children have last names that are different from their mothers. When people express the desire for all members of a family to "have the same name" for convenience sake, they're really making it much more difficult for those who don't have the same last name. By using the issue of names to trumpet a 2-parent family that fits a social ideal, are women subtly marginalizing those who don't have that 2-parent family that fits the ideal? My daughter and I don't have the same last name, by my husband's and my choice. And her friend Kaylee has a different last name from her mother (who remarried) and her friend Rachel has a different last name from her mother (who also remarried). Is it really important for us to be able to look at a family's names and judge whose biological parents are still married to each other? When did that become important?
Basically, women change the names they have had for over 18 years to the names of their husbands because they don't want to challenge the status quo. This is why I reserve a little bit more disdain for the upper middle class women who have tons of social capital already but don't want to give up this little bit extra in the name of understanding the varieties of family structures there are out there.
I probably have more reasons why name-changing is so offensive, but I can't remember them right now. I'm sure if anyone comments, it will be to challenge me, and then I'll remember the other arguments. :)