-ing or -ed: Endings in English
-ed tells us the effect that something has on someone. It is used to tell us how someone feels.
I am excited. (how I feel)
-ing tells us something about the subject; it describes it (not how it feels).
This movie is exciting. (about the movie)
I am tired. The meeting was tiring.
I am amazed by her work. Her work is amazing.
I am surprised! That announcement was surprising.