Agreed. Which in my opinion is why you need to reduce taxes and stimulate when times are bad, not increase. Also since you can't always reduce taxes, or they would converge to zero, you have to have a time when you increase taxes. When is the time to do this?Its not as simple as that. Different tax cuts will have different stimulative effects. You may find a situation that through tax cuts you actually stimulate the economy and increase revenue. This is what is referred to as the infamous Laffer curve.
You can for instance pursue a policy similar to Ireland's and attract FDI, foreign investments increased jobs + exports by pursuing a low corporation tax strategy. Indeed the Irish vehemently defended this during their IMF bailout package
Plenty other examples abound ..... but I guess you get the drift
In my opinion the best time to do that is when times are good, booming in fact. It will it will have far less of a negative impact at that time, and the revenues will be increased more dramatically then. Which is why I disagreed with Atilla, that you cut taxes when the yearly books are balanced and debt outstanding.