Nigeria is an extremely diverse country, with well over 1000 different ethnic groups residing within its territory. The 4 largest of these groups are the Hausa, the Fulani, the Igbo and the Yoruba. The culture of Nigeria is therefore every bit as diverse as you would expect from a country which is a melting pot of people from so many different backgrounds.
Generally speaking, Nigerians can seem very emotional to people of other cultures, as big shows of emotion in public are commonplace and perfectly acceptable. This may make it seem that people are having an argument or a shouting match, when in fact they are merely having a discussion or a friendly conversation, so try not to be put off by this.