Wiseblood
Adventurer
A) Fear is what you are feeling. The whims of the DM? They can do a lot. You make them sound like subjects in someone else’s kingdom.a) such things are typically a special ability, rather than at the whims of the DM; in fact, a PC can use a special ability to attempt to influence the way another PC is feeling, but under other circumstances it is bad form for another player to try to dictate how a player plays their character
b) note how the player gets a saving throw; it is the dice that are deciding, not the DM
c) even in the case of a failed saving throw, the player still has the ability to decide how the character feels within the limits of the effect; for example, the 5e frightened condition allows the character to continue fighting, albeit with disadvantage, if the player decides the character is both afraid and angry
B) rhetoric: The DM caused you to roll that save. The DM decided, the dice are consultants.
C) The frightened condition is a condition that is imposed to create a specific set of constraints and disadvantages. It may or may not involve you actually being afraid.
Feeling other feelings is unimportant fear is what you must act on.