I use them often in real life, but rarely in my writing. They do nothing to advance the story and they’re redundant. How are they redundant? If an expletive is the normal response to an event or series of events, the reader has already used the expletive in his mind, at least if the reader is a guy. Female readers, maybe or maybe not. I have no idea what goes on in the female mind. Anyway, I prefer to show the character’s anger/rage rather than use an obvious expletive; have the character put his hand through a wall or a face. That’s my view; others may disagree. Time for me to get the—– outta here.