Obviously. Life's different with kids. But sometimes you don't expect it when you're going overseas with kids, especially if you've done it without kids.
In my opinion, the biggest disconnect I've had between what I've experienced as a single person and therefore expected as a parent, and what actually has occurred as a parent, relates to language. Learning a new language is a lot more complicated that showing up as a willing learner in a new country. I can't tell you how often I've heard, before we've gone overseas with our children, that we'll all learn the new language quickly.
That's not exactly true. My husband and I are far from being inexperienced language learners (for example, with a little dusting off of Egyptian Arabic, he would test at at least a level two in speaking in four different languages besides English; I could do probably two right now with some notice), but the languages we've worked on as parents in new countries have been significantly more difficult than the languages we worked on before we were married.
Most of this is simply because when we were single, we could put ourselves in a nearly perfect language-learning environment (this was particularly true for my husband when he learned Spanish and was basically dropped into it, full-time, and had to learn to speak to survive). Arabic was a lot the same way. We learned a huge amount of Arabic when we lived in East Jerusalem, speaking Arabic all the time and taking a full load of Arabic classes. I do, however have an atrocious Palestinian accent.
It can't be the same here because we can't devote that kind of time to language learning, nor can we isolate ourselves from English speakers because our kids speak English. I spent at least 8 hours a day working on Arabic 15 years ago, but I can, at best, spend 2-3 hours a day on Russian right now, and those hours aren't as effective, and the family suffers when I spend that much time on it. It's obviously going to go more slowly.
There's also a really common myth that children just pick up new languages with no trouble. Yes, they'll usually learn languages more quickly than adults, but the setting matters just as much. If you're living in Europe you'll probably be able to send your kids to a good local school or international school than emphasizes learning the local language. Generally within a year your child will be speaking reasonably well if they're in a local school that's experienced in helping children who don't speak the local language.
But that will also be all that your kids learn that year if you go that route. That might be good, but it's not necessarily the best option for everyone, especially if the stay overseas is only a year or two, or if the language is fairly obscure. And if you don't have access to a school where learning the language is emphasized, then it's very unlikely your kids will become even reasonably fluent in a new language, or able to read and write in it, etc. Playing soccer on the street doesn't produce much language ability, even if lots of other good skills are learned while playing. (The situation is often different with younger children, say, kindergarten or younger, if you can get them into almost any environment where they're hearing the new language a lot. I wish I had a four-year-old brain sometimes.)
This is not to say that learning a new language isn't important or worth sacrificing for. It is. But it's also important to be realistic in what your family can do, and to figure out what's really important for your family. And I still hope that everyone in the family will get better at their new languages. It's so important to be able to speak to the people around you.
(I wish all Americans could experience this because Americans as a whole need a lot more empathy in our attitudes regarding language learning. We appallingly bad at it, both in the US or abroad, but have unrealistic expectations of those who come to the US without knowing English already.)