Much as I adore my DS I do miss some things from my 'pre-DS' life.
Like:
Just being able to say yes to an evening out without having to check with DH that he's not working late. Same goes for him of course. Because someone has to be home with DS.
Going on holidays that involve a lot of walking. DS is 11 now but when he was a little younger a few miles was his limit. DH and I used to enjoy hill walking or just going for a nice long walk at the weekend. With DS we had to drive part way as he couldn't finish the walk or wouldn't without a major tantrum which takes the edge off the fun. Tantrums didn't happen often because we try not to put up with them but it's not something you can anticipate and once it happens, that's it for the day. Moment gone. He was too big to carry by that point (as we could when he was a toddler).
Having to watch a family film on a wet Sunday afternoon when you really wanted to watch something creepy or more intense or a political drama sort of thing.
Eating out is child friendly. Not always McDs but not a very posh restaurant as DH and I would go to on special occasions because it had to have a kids menu. If we could afford the posh restaurant on special occasions we had to factor in a baby sitter and find one so it couldn't be a spontaneous 'shall we see if there's any room at x's tomorrow night?' Even going for a curry or Chinese meal was out really as DS, until maybe the past year or so, couldn't eat any of it so if the restaurant didn't do 'English-y' food we were on a hiding to nothing. So we'd get a take away and DS, give him his due, would try a little bit of whatever we were having whilst he had a different meal.
Definitely lack of sleep in the first few years. DS woke three to four times pretty much every night for the six to eight months, then went to twice a night but was up at 4.30am every day until he was three years old and went to nursery. And I do mean he woke early every day. Weekends mean nothing to young children. Even now he's up at 5.45am every day, no matter what time he goes to bed. I used to be the same when I was eleven. I'd be unable to sleep, get up and watch TV with my parents until 10.30pm - bet they loved that - then got up at 6am every day. Which is a short range of sleep for a child really. Even now I don't need more than six hours sleep. That changed when I became a teenager and wouldn't get up until mid day at the weekend - which caused a different problem!
Being an only child we try to encourage DS's friends to come over to play. Which is fine but the noise is horrific. So you get the respite from putting on a family film on that wet Sunday but then you have the noise of a force 5 hurricane charging around the bedroom when DS and his mates get going!
It's the spontaneity that I think DH and I miss. Getting home from work and deciding to go out for a drink in the pub and grab a bar meal instead of a proper dinner. Or ringing each other at work and saying do you want to stay in town this evening and eat out. Or, on a Thursday saying 'how about seeing if we can get a B&B room on Friday night and driving down to the coast after work then back on Sunday afternoon'. It can still be done but it involves planning and has to take homework into consideration.
Only being able to go on holiday in school holidays. Which is fine usually. But if you want to go somewhere weather dependent (like ski-ing or a far flung place) and that weather is best in mid March, you're at the mercy of the school approving the holiday during term time whereas when it's just adults you can go anytime you can get annual leave. Plus it's cheaper outside school holiday time - a big bugbear of mine.
So nothing insurmountable and it's worth the effort (life would be much, much worse without DS in it). But Facebook will only ever show you the little cutie in the pretty dress or the first day at school photo of the smiling boy. It doesn't show you that the little cutie has been sick on the first dress, thrown a tantrum because she can't wear mummy's shoes and has just tried to shave the cat. Nor that the smiling boy was wiping snot from his nose on his sleeve 2 minutes before the photo because he was panicking about school. Plus he woke half a dozen times during the night worrying about it or that he almost knocked his baby brother out last night when he whacked him with his box of Lego in a fit of temper.