Please use affirmative phrases when naming your boolean variables and flags - I find that it makes code much more readable. This is particularly true when naming the configuration settings used to turn features on or off. If the setting is named in the negative then I have to use a double negative to enable it, and everyone learnt in high school that double negatives are a Bad Thing.
For example, if I have a feature that sends emails and I want to make this behaviour conditional then an appropriate variable name would be “boolean sendEmail = true”. It’s easily comprehended. Contrast that with the same feature phrased negatively: “boolean disableEmail = false”.
It gets even more confusing when these variables get used in the code
if( sendEmail) {
sendEmail();
}
as opposed to
if( !disableEmail) {
sendEmail();
}
For bonus points, be explicit about the default value especially if the value is coming from a configuration file where it might be absent entirely.