Why can't my sims work out sometimes?

[simsfreq]

Why does "work out" not always appear for sims when clicking on the stereo? This happens to me with every stereo, and seems to be random. I thought perhaps it was because the sim was in a bad mood, and would refuse, but sims in a good mood can sometimes not get the option. (And sims in a bad mood get it but complain when you ask them to.) I thought they needed to be in the same room (I think they do actually) but sometimes even when they are in the same room it doesn't appear. Yes, the stereo is already on. My sims have not gained all their body points. And most confusing of all, it can work for a sim one day and not for the same sim in the same mood another day.

This has always happened and it's always bugged me. I have had it in these combinations:

Base game + uni
All except Pets & BV

Not to say it doesn't happen in other combinations, just that those are the ones I'm 100% sure it does happen in.

[Emma]

I've wondered this too-I thought it was because the sim was sitting down when I tried to give the action, but like simsfreq said, it can vary. I only tend to get my sim-kids without body career rewards to use the work out option anyway so it isn't a big issue for me. I'd still like to know why it only works sporadically though.

[J. M. Pescado]

This is a bug. Maxis incorrectly invoked the Fun Object (Exit) function, which means even hovering over the stereo can queuestomp you without the intent of working out, and cause the action to randomly not appear. It is fixed in the updated version of Stereo Hack.