- (bored- boring): That book was really boring. I fell asleep.

- (interested -interesting): I am not interested in board games but I love racing.

- (relaxed- relaxing): A long walk is very relaxing.

- (tired- tiring): The game was tiring but we had a great time.

- (excited- exciting): This game is really exciting!

You are asking the difference between human and inanimate, in a sense.  The adjective modifies the actor or the receiver of an action, but if the receiver in inanimate, it cannot be modified by an emotion.  So ask yourself whether the human subject or the object is being modified. For example, “Was the book bored?  Or did it bore the reader?”  “Was the game interesting?  Or was it interested?”  (In both these cases, the human reader can have emotions—boredom, interest—but the inanimate book cannot.)  Further, a walk and a game can elicit reactions in humans, but cannot “feel” emotions.  So, the walker gets relaxed and the game player can be tired.  The suffix “-ing” here means “causing or having the property or capability to” while the suffix “-ed” implies “being acted upon, being affected by.” So, the book was boring—I was bored; I am not interested in board games; a long walk is relaxing; the game was tiring; this game is exciting.