What are the factors responsible for variations in criminal liability?

There are a number of factors which lead to varying
degrees of criminal liability; almost all variations are based on the individual facts
of the case. Two examples, Homicide and Burglary: Homicide is the killing of a human
being by another human being. If it is unlawful, it becomes a crime. If it was
premeditated, that is "in cold blood," it is murder; if it is committed in the heat of
passion, it is manslaughter; if it results from gross negligence (playing with a gun,
etc.) it is involuntary manslaughter. If one breaks into and enters a dwelling at night
with the intent to commit a felony, one has committed common law burglary. If one simply
breaks in, say to escape from danger, he may have committed a lesser crime, but not
burglary. In every instance, the circumstances of the offense will lead to some
variation. Was there self defense, or some other form of justification, etc. All these
are factors that affect culpability.