Disobedience!
One day we got something like 37234 as the squawk, when one of those "Do what I tell you to do because dis be my country" discussions ensued for a short while.
Another time we got something like 3782, which led to another, similar discussion.
Of course we have all had to turn to heading 370 or make a right turn to 350 from heading 355 but that could happen anywhere, I guess.
One day I was on my way to Abuja when my buddy the Prince said there was an Airbus at our 3 o'clock and three miles, same heading.
"Ah yes, well. It is often so that another aircraft will appear to be at the same altitude when it is actually two thousand feet higher or lower. Let us see now... DAMN!"
Yes, well, there was a pefectly reasonable explanation. We departed Lagos for Abuja ten minutes ahead of A310 Whiskey Tango Whatever, cleared to F230, ETA ATD plus 1:10. The A310 departed Lagos at our ATD plus ten with an ETA of our ATD plus 1:00, cleared to F230. So we had ten minutes separation at each end. What happened in the middle, well...
The funny thing with that one was that ATC ignored their attempted homicide but tried to hang me the next week for doing a perfectly legal VFR departure from Lagos with an en-route transition to an IFR arrival at Abuja.
The very same A310 captain got all torqued when the little Cessna just blasted off while he was stuck there waiting for an IFR clearance that was never going to be delivered, due to some ATC industrial action. I could go 65 miles at 1 500 feet without burning all my fuel, when he couldn't, I guess. Life is unfair: get over it.
Since he was also some kind of Line Training Captain with some status at the NCAA he went whining like a little bitch to them to see if he couldn't get justice. I found it grimly funny that a gross error went ignored while a non-event had me trekking back and forth to see if I might not say something, anything, incriminating. Nigeria at its best, that was.