"Good" Mormons don't take recreational drugs, don't drink coffee or alcohol, will pay 10% of their income, don't have premarital relations. Mormon Missionaries follow a more stringent set of rules.
I stopped believing in Mormonism as a missionary, when living in Denmark proselytizing Mormonism to the world. I wanted to follow 'the rules' but this caused a huge internal struggle. It was two simple rules: "Don't knock on doors more than two hours a day" and "Proselytize as much as possible." The first was the 'rule' that came from the Mission President, an elderly gentleman who was supposed to receive heavenly inspiration for everyone within the mission. "Above" the mission president was what is called an "Seventy" or "Area Authority", and these two would contradict each other on other occasions. They didn't know nor acknowledge that they contradicted each other.
Another rule contradiction between the two was to not visit areas far away from our homes, versus to do so. I've knocked on very many doors throughout Denmark. I didn't believe in irritating people who had already rejected us.
This very minor contradiction of rules caused guilt within myself because I couldn't fulfill the paradox.
It sounds silly, but it's the truth.
It was these and other minor things that caused me to disagree (quite wildly, actually) with the religion. It took me years to decouple from the religion, which, clearly I'm not doing based on these posts. I would disagree with that last sentence; my experience in Mormonism gives me a background with which to relate to other experiences, but isn't directly related to current Mormonism. Allegories and stories are useful.
The rules contradicted each other, and I wanted to follow the rules.
Eventually I resolved this contradiction with a new, personal rule: "Rules are made to help people, but people are more important than rules." This rule is what made me outgrow Mormonism because Mormonism couldn't fit into this, what I felt was a higher, more important rule. It's the golden rule, but applied specifically to rules. It's very difficult to beat the Golden Rule: "Do unto others as you would have them do unto you". A close contender I think is, "Don't be a hypocrite. Be consistent."
This emboldened rule became my measuring stick. That idea was pretty important to me. People are more important than rules, so when a rule hurts more people than you harm, it is a rule that you should ignore nearly always.
I started this out on Mormonism, so I might as well end it on Mormonism. In order to be married within Mormonism within a Mormon temple, you're supposed to follow all of the rules to the best of your ability. There are strict things though - you can't go to the temple if you drink coffee. Can you imagine being the best person on earth, helping every individual as much as possible, and not being let into heaven because you enjoyed the taste of coffee? Can you imagine looking down on others because of this thing that is probably safer than many energy drinks that Mormons are allowed to drink? If there was a heaven that excluded all coffee drinkers, I'm certain coffee drinkers wouldn't consider that heaven. It's pretty ridiculous to think that people could be classed into inferior and superior categories like this: a group that drinks coffee and a group that doesn't. Condemning another person based on such a singular belief, about whether they drink coffee!, ignores every other aspect of a person that is in(credibly)-valuable.
So, there's an example of a rule getting in the way of recognising the humanity of others. Rules are meant to help people, not the other way around.
Everyone is valuable, everyone deserves love, including those that drink coffee and those that don't.