You are making assumptions rather than first providing
facts. For example, how do you know breakers on one side of
the breaker box would be on same phase? When a 240 volt
breaker is installed, it provides both phases from same side
of that box. Why does this make sense:
... breakers for the side of the house with the problems
would be on the same side of the breaker box.
That is only speculation. It is responsible to ask why this
strange failure occurred. But it leads to nothing useful when
you assume.

What could have caused the problem? Let's see. I only
have one idea. Therefore that *IS MOST LIKELY* the reason for
your problem. Some others posted using this logic.

You have provided woefully insufficient information for
anyone to post a probably reason. But even worse, your own
posts are based in speculation. No wonder others posted using
only speculation as a probable reason.

Every electronic appliance has a unique cutoff voltage.
These are numbers so necessary to appreciate what happened.
Intel even states how low voltage can go and computer still
works just fine. Voltage so low that incandescent bulbs are
at less than 40% intensity. Other appliances may cut out at
higher voltages. Again, without that number or knowing which
phase each connected to, then no useful facts are available.
Tom MacIntyre once identified a 120 VAC TV that worked until
voltage dropped below 37 volts. All other electronics could
shutdown while the TV worked? What does that tell us about
household wiring? Nothing.

Every appliance must also work so many seconds after power is
lost - as both Mark and PrecisionMachinisT noted. Another
number that varies depending on that appliance's internal
design - and that was not provided. Just more reasons why
what did and did not work provides nothing useful.

You don't have numbers. Your facts are mostly speculation.
Don't speculate as other posters have done. To learn, at
minimum, you must measure voltages between wall receptacles
that did and did not lose voltage. If for no other reason to
learn which phase each receptacle is connected to - without
speculating.

Choreboy wrote:
The flickering of the ceiling light lasted long enough for the lady of
the house to ask, "What's that?" and me to turn around and see it.

After finding four electronic devices scrambled in three rooms, she
checked the bedroom clocks, saying they always go out if the power
flickers. They were fine. It makes sense that the breakers for the
side of the house with the problems would be on the same side of the
breaker box.

The same transformer supplies my house. I have computerized stuff
plugged into both sides of the line, and none was affected. However,
the line that supplies my neighbors supplies another neighbor, who says
she had to reset her electronics after her lights flickered at the same
time yesterday.

I guess it's a splice up above. I see a couple of popped splice covers
up there; maybe they overheated sometime due to resistance in the
connection. Could a bad splice have welded itself during the
flickering? As it didn't affect my service I suppose I shouldn't be the
one to report it. What would my neighbors risk by not reporting it?

Choreboy