It's a natural reaction to use some sort of word or phrase when something bad happens. However, instead of using a bad word, you can use one of these alternatives instead!
You can also make up your own expressions, like "oh, hoochie-coochie" or "ah, cakepop." A friend of Talia Weisberg, the creator of Bleep!, made up shisnicks, and Weisberg's mother made up fadoodle. Weisberg herself often uses crud and frig.