Because of all the wars that happened, the Nephites became very humbled. They had lost family members, fields, flocks, and so much more during these wars. This enabled many people to feel the spirit, and 3500 people were baptized and joined the Church. I'd say that's great progress for the size of people that were there.

Over the next couple of years, the Lord blessed the people, but there began to be pride and inequality among the people, to the point where many members of the Church began to become wicked.

"and the wickedness of the church was a great stumbling-block to those who did not belong to the church; and thus the church began to fail in its progress." (Alma 4:10)

I think this is a rather poignant lesson to learn. As members of the Church, we must live the gospel fully. I have seen some examples of the scripture above. I have spoken to people who claim that they don't want to know about the Church because someone who was supposedly a "card-carrying member" had wronged them or at the very least had not been very Christ-like toward them.

This happens for a couple of reasons. One is just plain pride. It could come in the form of "I have more money than you", or even (ironically) "I'm more righteous than you". Another reason is because it's not fully understood. Or perhaps the person is just giving into temptation and being influenced by Satan. Whatever the reason, the wickedness of members of the Church can cause people to fall away or reject it. Thus the Church [begins] to fail in it's progress. That's how it happens overall.

It just underlines the importance of staying true and faithful. When you make covenants, keep them. When you live the gospel, live it fully. Yes, the Lord will bless you. Yes, you will probable even encounter such blessings that you might have the temptation to think you're better than others, or whatever. Just remember, when someone decides not to join or be part of the Church, and you are among the reasons for that decision, you will be held accountable to some degree for that persons choice. 

I want to be on the opposite side of the fence. I want to live my life in such a way that people see me and have desires to join the Church and be blessed the same way I have been blessed, to have the gospel in my life and the direction of the Spirit. I want others to have that too.