Consider a scenario, a rare disease introduced into a comfortable, western environment. The odds of the disease spreading are slim, but the odds of dying from the disease, if left untreated, can be very high.
Fortunately, there is a treatment. A few specialised antibiotics will completely cure the disease, especially if it is caught very early -- when it might still be indistinguishable from a common cold. A high rate of cure is desirable, as then there will be relatively little chance for it to mutate into something more contagious.
However, the greater the exposure to these antibiotics, the more quickly the disease is likely not to respond to them in the immediate future. Further, there is something of a limited supply of these specific antibiotics.
Those who horde and/or use these antibiotics now are unlikely to get sick at all -- especially any given person is rather unlikely to fall sick in the first place. Those who do not have access to the antibiotics take their chances. The more people use preemptive or "panic" antibiotics unnecessarily, the more likely everyone (except those people) is to fall sick in the long run -- perhaps even with a strain that is non-responsive to the antibiotic.
What do you do?