The people "making good choices" here being the unproductive office workers?

No, the people making poor choices are the managers wasting the work output of their office workers.

They're not usually bearing the cost, though? In a lot of places it's better to have hundreds of unproductive staff than a few productive ones, it inflates your standing and pay. It's ultimately the investors who bear the cost, but they also deem it not worth their time to try to manage the managers.

Sorry to just jump in here, but growth isn't for everyone. If some people don't want to work, I'd rather pay them to get out of the way than risk the chance of them adding negative net value.

That’s the other major issue of UBI — it’s an ideal tool for ghettoization, if those in power decide it’s more profitable to give “undesirables” just enough that they’ll get out of the way — and stay there, quietly.

The wealth and culture gap would become nearly insurmountable for anyone otherwise capable of upward mobility out of the UBI class.