I am aware of this and I agree with it.Fundamental principle of psychology: All human activity is aimed at the end of generating positive sentiment.
In short, people simply wish to feel well.
Interacting with other people gives them direct affirmation. For example, they are rewarded by their community for behaving in a certain way. They strive to behave in a way that leads to their reward.
Secondly, one's intellect makes it obvious that some questions of life are difficult to answer. Man knows that some things in the world are undesirable. In order to feel well, he looks for reasons to believe that he will be alright. The religious community claims to know everything that man needs to know about the world and how he must behave in it. The community promises to bestow such knowledge upon the individual if and only if he behaves in a way community would like for him to behave.
Therefore, to answer all of your questions, people engage in the acts you have mentioned for two reasons. Because they see immediate gratification follow as an entailment of such acts (or the community rewards them for such behavior), secondly, it leads them to believe that doing as they do allows them to know exactly how they should live their lives.
This is the underlying rationale of a conventional person with regard to why he participates in religious activities. However, most people are not aware that this is what is driving them, as they simply do not reflect. However, if we were to explore their mindset thoroughly or challenge them to discover their true motivations, this is what we will have discovered.
Most people, however are not truly religious. They are simply doing as they are supposed to be doing because they do not know any better. People who do not think for themselves allow for their community to instruct them exactly how they should live their lives. Religious community provides exactly this service.
The level in which I am interested is personal level.