Fiber-rich corn is good for you, but it also contains cellulose, a type of fiber that humans can't break down easily because we lack a necessary enzyme. If you chew corn longer, you can probably digest it just fine but wolf it down and it may pass through you undigested, and cause gas and abdominal pain.
Other food that could cause indigestion if you over eat are raw vegetables. Raw vegetables contain a lot of insoluble fiber that, like corn, can cause bloating, gas, diarrhea and cramps when they pass through your system undigested.