Feeding vegetables question

I have a question regarding feeding our canine friends fresh veggies and/or fruit.
What's good, what's bad, what's your general experience? Anything I should absolutely avoid??
Thanks!!

Green beans, carrots, slices of apples & pears were the veggies/fruits of choice for my parents' English cocker after she developed pancreatitis and afterward had to be on a low-fat diet. I've only had a couple of dogs who would eat veggies, and green beans were their favorite. Mom's Rottie loved carrots. Avoid grapes/raisins, onions.

Do as Snark has said above. As for what to avoid, Cherries, Mushrooms and Apple Seeds.

So basically avoid everything with seeds ?