Since I am a man, I know, at least for me, alcohol tends to have the highest ROI. Now this isn't the case for all men, it may induce more stress in some cases. But, generally, for men, alcohol tends to have the highest ROI. This is probably why more men have become alcoholics (although I have heard that the number of women becoming alcoholics is on the rise, is that due to the recession?)
What about for women? I don't know. I would like to hear your opinion on it. So, simply rate things by how much stress they relieve and then divide that by the cost of the thing. So, for instance, going on retreat: let's use a 0-100 scale for the stress relief. Maybe it has a 90 for stress relief, but it ends up costing 500$ for the plane ticket and 1 week of pay. Whereas, a date might have a 30 for stress relief, but only cost 50$.
What are your ideas for relaxation?