Personally, I have a smartphone and have no intention of giving it up. It's just too useful, between taking photos, using GPS, playing games if I'm stuck somewhere and am bored, using RealCalc (RPN calculator app), plus of course voicemail, texting, etc. I rarely use it for email though; I wait until I get home for that. Email is, by definition, not that urgent IMO.
I really don't understand why a bunch of people here feel like they need to get rid of their phone, or put it in airplane mode, or get a dumbphone, or whatever. I guess you all have a whole lot more friends and family than I do. If I don't want to be bothered by people, it's simple, I just go about my business and no one calls or texts me most of the time. And if someone does at a bad time (and half the time it's a wrong number or something anyway), I just ignore it.
Of course, as a few people mentioned, I don't have Facebook installed on my phone either. What a waste of time (and battery power).
As for hanging out, that's easy: if you're having a conversation, don't get your phone out and mess with it. Is that really so hard? I keep mine handy on my belt holster, and if I'm talking to someone, it stays there, unless I have a really good reason to whip it out, such as wanting to show them something on it. I'm not the most socially-adept guy around, but even I know better than to get my phone out when I'm talking to someone and use it (like for texting) to the exclusion of that person's attention.