While composting there are some materials that you have to watch out for. Using the wrong materials while composting, can result in many things, including attractions of pests. Here are some examples of materials not use during composting and how they affect your compost.
Bread related products- attracts unwanted pests
Cooking oil- also attract pests and animals
Glossy paper and magazines- does not breakdown and ads chemicals to your compost
Meat- compost becomes smelly and attracts bugs and animals.
Milk-also attracts pests while making compost smelly
Rice- allows bacteria to start growing in the compost pile or bin
Walnuts-makes soil toxic for some other plants
Paint- just doesn't belong in the garden
Acidic fruits like Citrus fruit- highest pH level of soil.
Animal or human waste- negatively affects health of surroundings.