I was looking for a translation of the German expression "bevor ich mich vergesse" (lit. before I forget myself) and looked up if the literal translation could be used. In German this expression conveys a threat or warning.

However, looking at several dictionaries confused me a lot as the dictionaries seems not to agree with each other.  

The first two quotes I provide below get close to the German meaning, but unfortunately they don't provide any examples. All the other ones have a totally different meaning.

> 
> [forget (oneself)](http://www.thefreedictionary.com/forget+(oneself)): To lose one's reserve, temper, or self-restraint.  
> 
> [forget oneself](http://www.merriam-webster.com/dictionary/forget): to lose one's dignity, temper, or self-control
> 
> 
> [forget oneself](http://idioms.thefreedictionary.com/forget+oneself): to forget one's manners or training. (Said in formal situations in reference to belching, bad table manners, and, in the case of very young children, pants-wetting.) 
> 
> 
> 
> > 
> > John, we are going out to dinner tonight. Please don't forget yourself.
> > 
> > 
> > 
> 
> 
> [forget yourself](http://www.urbandictionary.com/define.php?term=forget%20yourself%20): to act boldly or arrogantly. Phrase used to humble a person.
> 
> 
> 
> > 
> > I believe you forget yourself sir! 
> > 
> > 
> > 
> 
> 
> [forget yourself](http://www.oxfordlearnersdictionaries.com/definition/american_english/forget): to behave in a way that is not socially acceptable 
> 
> 
> 
> > 
> > I'm forgetting myself. I haven't offered you a drink yet!
> > 
> > 
> > 
> 
> 
> 

I'm pretty sure that each of those definitions is correct, but probably some of them are only true for certain dialects or set of dialects.

I think my question now is if you would hear or say "forget yourself", what does that expression convey? Which of the definitions above could be applied?  

Is there a definition which is acceptable for most dialects, i.e. is any of those understood in most parts of the world?

Finally, can this expression used as a threat or warning as in German?  

Examples:

> 
> Hau ab, bevor ich mich vergesse. (lit. Take a hike, before I forget myself.)  
> 
>  Verschwinde, oder ich vergesse mich gleich. (lit. Get lost, or I'll forget myself.)
> 
> 
>