Alignment Does Not Create Actions

I'm sure a lot of us seen this happen at some point..."I kill the homeless beggar!"..."Why?"..."Because my alignment is evil." However, such a player has the concept of alignments reversed. And this might be part of why some people dislike the concept of alignments in the first place (or at least part of the reason).

Alignment does not cause a person to commit an act, instead acts define the alignment. 

If a character with an evil alignment kills a homeless beggar it is not because they are evil, it is because they are homicidal. The act of killing randomly for the enjoyment of it is what tags a person as having an alignment of evil.

Some players see an alignment as a blanket that covers everything that could possibly fall within that description. However, truly evil people do not commit every type of evil act "just to be evil". There is no record of Hitler kicking puppies for the fun of it.

So, alignment is better expressed as a result of actions taken by a character, even potential actions. It seems like alignment needs to better defined, or at least more narrowly. For example, an evil character might be "homicidal" or "likes to inflict pain" or a "kleptomaniac". A good alignment might be defined as "caring" or "unselfish". Neutral might be "callous" or "unbiased". Instead of giving a character a blanket alignment, narrow it down to what they actually have a predilection for doing.

And that is part of the problem with alignments. They can be a straight-jacket. For instance, an evil aligned character might commit genocide, but is kind to puppies. Having an evil alignment does not automatically mean the character is evil 24/7 all the time in every situation. People, and well-done characters, are more nuanced than that. This is easier to accomplish if an evil aligned character has defined areas where/when they are evil, with the assumption that outside of those areas they are "normal".