The phrase "don't say it, don't say it" is a corruption of "don't say it, don't say it, don't say it. The phrase "I told you so" is an emphatic double negation of "I told you so," which in essence means, "I told you so. When someone ignores your advice and makes a mistake, you say, "Look at that, that's what I said," probably with a feeling of "Suck it up. However, the "advice" given in advance by the person who says such a thing is often a light-hearted word that comes out of his mouth, such as "You should be careful here. If you are a serious person, don't get too depressed if you hear someone say, "I told you so," in a pompous manner.
>>384 Shut your stinky mouth.