Money
There are a number of dilemmas one can have through their lifespan. Some of these include arguments with friends of family, sicknesses, and troubles with money.
The average American family had many children.
Arguments over who owns a certain amount
There are many reasons but I am not sure which one will suit your case. Remember this though, Your family loves you and they always will but we all have our arguments . You just need to open your eyes and realize what is important.
the number one cause of an engine fire would probably be oil leakage.Source: Experience
The number one cause of collisions on the freeway is following too closely (tailgating).
probably not number one but a huge cause of many deaths
cause
That can be one cause to one problem but not to all problems and definitely not the only cause. Your question is not very specific.
The largest number of cousins in one family would depend on the number of siblings in the family and the number of children each sibling has. There is no specific limit to the number of cousins in a family.
The number one cause of rust is oxygen. Water accelerates the process but it can't happen without oxygen.
If you are asking "what could cause one" then there are any number of things...if you are asking "how to cause one" then you sicken me