We have all done it: went a little overboard with a dash of salt, misread the measurements, and added a bit too much spice. It may seem like all your hard work will go to waste in this instance, but don't lose hope yet. The two most common occurrences of over-seasoning are with salt and spice, so we will focus on those for now.
If your meal comes out a little spicier than intended, the best way to combat it is with dairy. Dairy is a natural neutralizer and will mellow out the spice in your dish. A few spoonfuls of sour cream, plain yogurt or even heavy cream can turn your meal from a fiery volcano of pain into a perfectly spiced delicacy.
Now, if you add too much salt (or sugar, similar tips apply), there are a few things that you can do.
You can dilute it with water or broth if it is a soup or something of the sort or, you can add more of other elements to the dish. You can also play around with ingredients with competing flavours. If you find your stir-fry a little too salty, a pinch of sugar will bring it back down to Earth. If you have over-salted a piece of meat that is beyond saving, change your dish for it to become a smaller element of something more intricate, like a stew, rather than having it as the star of the show.