The key insight is that there's an emotion inside people's heads that's driving their decision-making. You can't see it, and if they're good negotiators they don't want you to see it, but it's there and it'll remain there even if you don't accept the offer.
If they gave you an exploding offer, then that signals that the emotion is "We really, really want you, and we're afraid someone else will snap you up." If it looks like someone else snaps you up and then you suddenly, miraculously become available a month later - what's the emotion? It's usually elation that you happen to still be available.
The one exception is people who are susceptible to sour grapes. "Well, we can't get you, therefore we didn't really want you in the first place." These offers disappear, but you often don't want to work for companies like this anyway, as it shows that management can't get over personal feelings of rejection to do what they'd judged rational a month earlier.
BTW, this is why it's usually not a problem to return to a past job that you've done well at and left on good terms. They liked you then, there's no reason why they wouldn't like you now.
If they gave you an exploding offer, then that signals that the emotion is "We really, really want you, and we're afraid someone else will snap you up." If it looks like someone else snaps you up and then you suddenly, miraculously become available a month later - what's the emotion? It's usually elation that you happen to still be available.
The one exception is people who are susceptible to sour grapes. "Well, we can't get you, therefore we didn't really want you in the first place." These offers disappear, but you often don't want to work for companies like this anyway, as it shows that management can't get over personal feelings of rejection to do what they'd judged rational a month earlier.
BTW, this is why it's usually not a problem to return to a past job that you've done well at and left on good terms. They liked you then, there's no reason why they wouldn't like you now.