Basic Trope: A show refuses to use swearing, preferring to use more childish workarounds.
Straight: Bob is a full-grown adult, yet verses his displeasure with phrases like "goshdang it!" and "oh, crud!"
Bob is a Mafia don who's just seen his entire mob gunned down by Inspector Javert and a squad of cops. It comes to the final showdown, and he comes out, guns blazing, screaming "DIE, you... doodooheads!"
In the entire universe where the story takes place in, they ARE considered swear words. Fuck is the more toned down version of Fudge.
Bob is around kids a lot, and prefers to use those variants on the words.
Bob's religion frowns upon cussing, or even forbids it entirely. But, Bob is only human, and thus is prone to displeasure (and the need/desire to voice that displeasure) now and then, so he works around the "No cussing" rule this way.
Bob personally finds swearing distasteful, but this is a deliberate character trait rather than a demand of the Moral Guardians.
Serious swearing is concealed behind a Narrative Profanity Filter, but the milder ones are quoted verbatim. "Bob proceeded to call Charlie a git, a jerk, and several other things the author would blush to reproduce."
Deconstructed: Bob sees his refusing to swear as a mark of deep personal morality, balancing out his less salubrious qualities such as serial puppy murdering. He's contrasted with a foul-mouthed hero in a story with An Aesop about censorship being Bad, M'kay?
Reconstructed: Bob knows how to swear... he just prefers not to.
Played For Laughs:
Bob curses all the time when he's calm but when he's in rage mode, he'll start using "Gosh dangnabit"-ish swears.
Bob is a gritty, chain-smoking Badass who is surrounded by people who swear like sailors, but he never uses anything more harsh than "friggin'." People are too scared of him to ask why.