What you don't want to see on your United Airlines flight 328 from Denver to Honolulu:
(It landed safely.)
Much nicer to see something like that just after takeoff, instead of in mid-Pacific!
On the subject of looking out the window & being a bit disturbed, I recall, back in 1968, looking out the window at the wing of a Viscount & being a bit worried that the riveted panels seemed to have largish gaps, rather than sitting flush.
I put it down to a jaundiced view of the Viscount, compared to the Fokker F27 I had been travelling in previously, which had a short take off distance & a fairly spectacular climb rate for an airliner.
With the much bigger & older beast, I was surprised by how long it took to reach operating height.
About when the flight attendants were normally handing out "munchies" & pouring coffee in the F27,the Viscount was still groaning & moaning to gain height.
With nothing else to do, I returned to gazing out the window, & apart from the rough looking constuction of the panels, compared to the Fokker, noted a large amount of wing flex.
"Don't be sillly!", I told myself, it just looks different, not necessarily worse!
Sadly, a couple of months later, on the same route, that aircraft "fell out of the sky"--------& yes, a wing fell off!