Garlic
Pressed garlic will be stronger in flavor, because the press basically smashes all the cell walls in a clove of garlic. When garlic is crushed, chopped, minced,or otherwise damaged, alliin reacts with the enzyme allinase, which results in the transformation of alliin into allicin.
Allicin is the stuff we like about garlic, and the more cell walls you breach in garlic preparation, the more of it you get, and the stronger the flavor. So, the larger the pieces of garlic used, the milder the flavor, and the smaller, the stronger. Using a press results in about the smallest "pieces" you are going to get, and so will make your garlic stronger in flavor.
Allicin breaks down pretty quickly if the garlic is heated or not refrigerated, which is why most chefs look down their noses at the pre-minced or crushed jarred varieties you see in the produce aisles at the grocery store. Buying your garlic this way is pretty much the same as buying pre-ground, canned coffee, or pre-ground pepper.
For those of you who don't want to clean a garlic press, you can achieve pretty much the same results with the smooth side of a meat mallet and some plastic wrap.
Just remember that the smaller the pieces, the more susceptible they are to burning with certain cooking methods, like sautéing. Burnt garlic is bad.
Another thing you can do as a "cheat" is, if you have a decent juicer, you can juice whole heads of garlic, (many of them) put the juice in a small spray bottle in the fridge, and use that to hose down any foods you want the flavor of garlic in or on. Cut the woody portion that holds the cloves together off before juicing, and go easy at first when you try it in your cooking. This stuff is really strong. You can also dilute it with water, or put it in extra virgin olive oil. Try using the diluted versions to spray a salad, or a hunk of meat before cooking. Yum!