When I hear "Nigeria" my mind automatically fills in "scams", as it has been one of the single largest sources of attempts to defraud on the internet. However, at work we actually have a great customer in Nigeria... In fact, someone from the office has been elected to go to Nigeria to do some training, etc. (not me! :-) )
I've also heard that Nigeria, while not currently overtly dangerous, can be somewhat prickly to westerners who do something as foolish as walk around on the street without a guide. I've also heard that riding in a taxi is a pretty bad idea, because there is a fair chance that the driver will just drive you out to the middle of the desert, mug you, and leave you for dead. (Keep in mind, I've just heard this from other muggable westerners, none of whom have actually been there, but one claimed that they heard this stuff from the "embassy", so it must be true.)
Imagine my surprise when I ran across this little gem this morning - no wonder nobody wants to ride in the taxis there. This one doesn't even have an altimeter.