There seems to be two very different ways that the phrase "social contract" is used.
The first is an unspoken conduct agreement between two people. If you hire a great guitar player to teach you guitar lessons once a week, are you allowed to cancel? Is your instructor? How much notice? Is it okay if he's drunk or halfway-preoccupied during your lesson?
How much formality is there? If you don't do the recommended lesson from last time, how disappointed will your instructor be?
How prepared must you both be?
This is a social contract that's actually a social contract. Sure, there's edge cases - even if it's expected that both of you are always at the lesson on-time, prepared, and ready to go immediately, there's still an exemption if you have a family emergency or serious illness or whatever.
But by and large, an honest-to-goodness social contract is how you, individually, carved out your expected conduct with another individual or group of people. This happens over time, by acting and reacting, and people modifying their conduct based on other people's behavior. If your instructor is sometimes unprepared and preoccupied, then you'll probably not feel as much pressure to be prepared and on time. Or maybe he's allowed to be sloppy, because he's a genius, but you're expected to bust your ass anyways. Social contracts can vary, there's no one social contract.
I've heard this meaning of the phrase "social contract" before, and it seemed sensible. There's also a second meaning of social contract, which is something along the lines of, "How other people around you expect you to act, and which there will be either physical or status/social consequences if you deviate from acting that way."
I've heard this called a social contract before, but I think it's inaccurate. You know, I've got some training in contracts. I studied it some (at one point, I was leaning towards being a lawyer), and I've written plenty of contracts in real life, both for deals I've done and to help friends out who needed a template contract but couldn't afford or didn't want a lawyer.
So when I heard the phrase "social contract" to apply to something you didn't agree to and you aren't getting consideration (legal term) for, my mind kind of reeled a little bit.
This second use of "social contract" seems flawed to me. A more correct rendering for this would be "social mandate" when strongly-enforced by physical consequences, "social expectations" when strongly-enforced by social consequences, or "social pressure" when weakly-enforced by social consequences.
Of course, a person giving out a mandate doesn't want to say they're giving out a mandate. If someone is saying, "Do this, or I'll punch you in the nose," they'd much rather you think it's a contract. "I hereby agree that I shall do this, or I shall be punched in the nose."
But note! For a contract to be a contract, you have to get "consideration" - you have to be given something by the other side. Otherwise it's not a contract. Seriously, look it up, a contract ain't a contract unless both sides get consideration of some sort.
Now, is not being punched in the nose consideration? Certainly, a state of not-punched-in-nose is superior to the state of punched-in-nose for most people. But I think it's fair to say that, no, taking an action under threat of consequence is not consideration.
Mandates are fine, of course. Every society needs them. There also is a lot of value to social expectations (so everyone can be broadly on the same page with default conduct) and maybe there's even some value in social pressure (I tend to think it stunts people far in excess of gains from it, but then, there's some very nice places with high levels of social pressure, so maybe I'm mistaken).
Thinking through this specifically - "What does social contract mean?" has been helpful to me. There's real social contracts, which you actually agree to and establish by your conduct over time. Then there's these things that people claim are social contracts, but which really aren't - they're either social mandates, expectations, or pressure.
Those aren't bad, either. They're not a contract, because you didn't explicitly agree to them and probably don't get explicit consideration for abiding them (other than not having consequences upon you). But the next time someone says, "There's a social contract!" - well, you can stop and evaluate. "Did I agree to this explicitly through my actions? Am I getting explicit consideration that I desire?"
If not, it's not actually a social contract... it's a mandate, expectations, or pressure. That's fine, those are good and necessary as well for society, but they probably should be reasoned about differently than contracts. Voluntarily entered contracts are more or less sacred, whereas mandates should be evaluated more on the basis of the authority of whoever is giving the mandate. Specifically, is their authority legitimate to you? And if not, do they have enough illegitimate authority to enforce their will on you anyways?
Social expectations and social pressures... well, those probably deserve a whole separate post some other time. One of the nice things about being a world-traveler is that people broadly understand and expect to negotiate social expectations with you, which isn't usually available to people within the same culture.
Social pressure? I try to basically just ignore it and do all my calculations on reasoning and what I think is right rather than consequences, but I don't recommend that for others since it makes for quite an uncomfortable life much of the time.
Anyways, those last two are a broad topic for another time. Today we covered social contracts - of which there's the actually-a-social-contract variety, and the social-mandate-masquerading-as-contract variety. Because they're very different things, I'd recommend you evaluate them differently.