You have to watch out for the defilements that might be motivating the thinking. You need to know your thoughts and your feelings so that you can identify if there are defilements in the process and clear the defilements so that you do the thinking you need to do without the defilements.
When you need to think you cannot not think. At that time, you have your thoughts and your feelings – and you want to check if there are defilements; and if there are defilements, you want to clear them first. You clear them by watching your feelings and when the feelings are cleared, then you continue what you need to think.
That’s what you have to do at work – you can’t work without thinking. You have to plan.
You’ll know that defilements are there because you can feel them – it’ll not be comfortable; there will be suffering, tension, stress. Basically, if it’s stressful, there’s defilement.