Not buying it. This is my largest problem with all of the alignment systems out there. Largely due to the fact that perceptions of what is good and what is evil vary. Most people believe what they're doing is either good or for the greater good, at least initially.
Mad scientists believe they're advancing science.
Politicians go in hoping to make some changes. Then a little change begins, the mad scientists doesn't realize he's crossed the line and is surprised when the townspeople begin mobbing his home. Politicians can't take the bureaucracy, but don't want to give up the power or lifestyle that they've gained. There's always motivation behind their actions. Every non-player character presented by the GM in a game should have some motivation for their actions.