Why congratulations?

So, it's like this, some people you know are getting married. They may be close friends, relatives perhaps, or merely acquaintances. They are a cis-gendered, heterosexual couple with an unremarkable age difference, they share the same beliefs and cultural heritage. You've just been told they are engaged, or perhaps you're writing a message for them on the occasion of their wedding.

There are a number of things you might say but I'll bet "Congratulations!" is right there at the top of the list of appropriate sentiments to express. It has certainly been my default message, "Congratulations and best wishes, love Mim" (Damn I'm bad at writing on greeting cards.)

Why? Why congratulations? Has someone won a prize? Overcome some great obstacle? Excelled at something and is therefore deserving of a reward?

I started thinking about this pretty much out of the blue and when I got to the "won a prize?" question my brain yelled "OH ICK!" because it brought to mind all the worst phrases used to describe two people getting married. He has won the girls hand in marriage - she's a possession. She has caught herself a man - how exactly, by trickery?

Then there's the obstacle thing. I can see congratulations being a sentiment I might very much want to express if the couple in question had been forced to battle for their right to choose to marry, but really, that couple I described above are taking the socially approved path, far from a path strewn with obstacles, they are cheered on by all and sundry.

I'm thinking that from now on I won't be saying "Congratulations!" when someone tells me they are getting married, instead I'll go for something along the lines of "How wonderful, I'm so happy for you both and I wish you all the best for your future together." It takes a little longer to type but it has the virtue of saying what I mean.*


*Actually even that phrasing makes the assumption that marriage is an unequivocally good thing, which I'm not at all sure is true, but I figure if two people have decided to do it they clearly believe it's a good thing for them** at any rate.

**Let's not enter the territory of the couples for whom the first thing that pops into your head is "Oh dear god, you're kidding!" or something along those lines.