Forgot and have forgotten

[Bonychat]

I forgot and I have forgotten....tell me the difference.

[Jaro7788]

Well, it all comes down to the difference between the Simple Past and Present Perfect tenses. Technically, you'd say "I forgot" when the fact that you forgot has little or no impact on the situation you find yourself in at the moment (or, when the time period in which the act of forgetting took place is clearly specified and closed, e.g. yesterday or two days ago). "I've forgotten" when it's the other way around. When there's no way of determining whether the act of forgetting belongs to nothing but the past or it still has an impact on your current situation, the two versions are fairly interchangeable. And remember: tradition has it that the Americans would rather use "I forgot" while the British would go for "I've forgotten". As long as it doesn't break the rules of grammar, though!

[Flyingzhang]

"I forgot" just means you forgot something at some pasted time, while "I have forgotten" emphasizes that you still cannot recall the thing you have forgotten.