Electrical Fire Averted…

So Christmas Eve, K and I are sitting in the living room playing cribbage. Suddenly the lights in the LR, just the LR, go out. As does the stereo and the computer streaming music to it.
I fiddle around with cords and plugs and breakers in the panel down in the shop but have no idea what’s wrong. It’s late, so I promise to fix it another day and we go to bed.
Christmas Day we have other plans so I run an extension cord from the next room and get things working again. I hide my indignities under a throw rug and hope my North Seattle Community College Electro-Mechanical Technology professors from 45 years ago don’t drop in on my right now.
Finally, Today, the 26th, I settle down to diagnose the problem. I noticed that one of the other outlets in the next room was acting flakey also. A nightlight was flickering on and off.
Pretty soon it becomes clear that this particular flakey outlet is on the same circuit as the living room outlets and in fact it is THE FIRST outlet in a series of outlets. All other outlets get their power from this flakey outlet.
I turn off the breaker for the circuit, remove the flakey outlet and what do you know, one of the four wires (two coming in from the panel, two exiting to the other outlets in the living room) IS LOOSE
Further more, the plastic near that wire is all yellowed from excess heat. (See the image below.)

So I shop at the local hardware store for a heavy duty contractors grade outlet, install it, switch the breaker back on, and Viola! Everything works reliably again.
I wonder how many other outlets are about to fail and if they will give me as much warning next time???