I have worked with innumerable Nigerians and they were all well spoken, hard-working and motivated with no desire to return to the sh~thole they had come from.
“”they were all well spoken””
I saw a few of them come through a flight school where I worked in Southern CA years ago and they spoke beautiful English. One would call me at the office and give me his name and I told him it wasn’t necessary as I didn’t know anyone who spoke English as beautifully as he did and I always knew him from his voice. He was a super neat guy. He got his family out of Nigeria and moved to Canada.
There were others from Nigeria who you wouldn’t trust as far as you could throw them - LOL. Had a lot of students from other foreign countries as well but can’t say much for their manners - especially anyone from France. They were the rudest of all. I had a Saudi student apologize for the way a French student talked to me in the office one day. Sorry - for digressing!
Many of the ambitious ones leave because the moment one of them becomes visibly successful in Africa, everybody even remotely related to them shows up with their hands out. And according to tribal custom, you have to accommodate them, even if to your personal detriment.