That's a good question. When I grew up (1970s), the word was the worst possible for my parents. You didn't say it. Other words weren't as much a problem, because they weren't used as much. We were just starting to separate "suck" from its implied sexual meaning, and we were starting to say it in normal conversation. For my parents, that's all it meant. For my kids now, it means "bad," and no more.
My parents used "son of a gun." They didn't know what it meant.