Back in the 1950s, physicists noticed that certain heavy particles (sigma baryons, lambda baryons, & K mesons) have significantly longer lifetimes than physicists originally predicted just based on their mass. Gell-Mann and Nishijima introduced "strangeness" to explain the long lifetime. Today, the explanation goes like this: particles containing a strange quark decay more slowly, because the strange quark can only decay via the weak interaction.
But nothing about that argument is unique to the strange quark. All quarks decay by the weak interaction. So what makes strange quarks special? Why do hadrons containing strange quarks decay so much slower than hadrons that don't contain strange quarks? (If a specific example is helpful: why does uuc decay so much faster than uus?)
I've read this answer, which describes a similar argument about the long lifetime of hadrons containing strange quarks. But in the linked answer, it seems like we could replace "strange quark" with "charm quark" and every statement would still be true except those about having a longer lifetime. We can't just point to the slowness of the weak interaction when distinguishing s-containing hadrons, because all quarks change flavor only via the weak interaction. What distinguishes the strange quark; what else is responsible for the longer lifetime of s-containing hadrons?