It's constantly annoying when my sim is listening to someone, then I accidently cancel my sim's listening to another sim by telling him to tell the other sim a story. Is there a way to stop it? Mods or anything?

That can be annoying, yes but I've never heard of any way to stop that behavior. It's also a blessing sometimes as often my sims conjure up the last thing in the world I would ever want them to do by way of Free Will or something that is going to take them an inordinate amount of time at what seems like just same instant that I issue them a command. If my command didn't supersede theirs, often I wouldn't even notice that they were going to do something else first.

Absolutely! I was naive and new to WA. I had a sim who wanted to buy a snake charming basket. He got one. On the first day of a 9 day vacation.
(I also stupidly let him learn all 3 Egyptian songs)

The only way to maintain sanity until I could access the family inventory to hide the stupid basket was to keep constantly queueing up actions.

Wait what's wrong with having him learn the songs?

I notice in conversations when the sims get a topic canceled, they'll usually finish saying what they were going to say to begin with.

Without a mod to prevent it, a sim who learns songs sings them. And sings them. And sings them even when someone else is singing a different one. And sings them long after you've gotten tired of them. And sings them while listening to the stereo. And...

(Well, you get the idea.)