1. Long Term Implications of eating GM Foods: You know what, it may be good that the scientists can prove that GM foods are safe to eat right now. But what about the long term implications of eating said food. How many tests have been done which show what would happen to a person if they ate GM foods over 20 or 30 years. This bugs me, but not as much as point number 2.
2. The cocktail of chemicals. We are eating far too many chemicals. Every food that we eat has so many bizarre ingredients in it and worse, foods that seem natural have been grown with x amount of even more bizarre fertilisers and chemicals. And here is the thing that annoys me most about the vast array of chemicals in foods: yes, I am sure that you can prove that ingesting chemical x right now (or even over the long term) may be acceptable (however most chemicals do cause significant damage to the body over long periods, google 'aspartame') . But what about the impact that chemical x of food x has in combination with chemical y in food y? We don't only live off a single food, we all eat a vast array of foods. If you cannot prove that chemical x in food x is safe for people to eat with all the other chemicals that they ingest in their body, then you shouldn't be allowed to sell food x. Simple as that.
It annoys me that the government has been so complacent when it comes to these ideas. They once again lack common sense, unable to see the long term social implications of their complacancy and only seeing the immediate dollar profit they can make by allowing food x on the market.