Dishwashers are there to make life easier right? Well sort of. But you really shouldn't put EVERYTHING in there. Here's a list of all the things that you should actually wash by hand and why:
1. Nonstick cookware...The abrasiveness of the dishwasher soap can actually wear the nonstick finish off
2. Anything wood....The heat and the wet and the soap can warp the wood...best to scrub them with baking soda instead
3. Cast iron skillets.....Not only can it wash the "seasoning" away, but it can also rust them
4. Aluminum cookware..... metal can oxidize. Stainless steel is ok to put in there tho!
5. Anything copper, silver or gold...tarnishes the metal
6. Some plastic items....heat alone can melt the plastic if it's not dishwasher safe
7. Sharp knives..... Soap and heat will dull them and loosen handles....wash them by hand