I cannot and do not smoke when I need to interact with my employees, investors or partners as I find it very hard to be at my sharpest wit verbally. So when my schedule calls for that, I skip.
However, there are many other times when I find my smoking to be a secret weapon: 1) There is zero question that I'm at my most creative when smoking. Sometimes a solution to a product or marketing challenge seems hopeless. In that instance, a smoke seems to unfog the mind and ideas that I never had sober just jump into my head. Good ideas. Ideas so good that if anyone around me knew how I came up with them, they'd probably be shocked. 2) Coding - A smoke will focus me for hours on coding. Sometimes I have a smoke, start coding and what feels like a blink of the eye is 3 hours of the most productive coding I'll have all day. It's false to think that the code is of poor quality, quite the opposite. I find that the mental model sustained in my head while coding becomes even more clear - it's like instead of just visualizing the model, it's like I'm inside it.
Some commentors have complained that they become lethargic or foggy. I'm sure that individuals react differently, but what I've found is that Indica strains should be avoided - they tend to have that effect on almost anyone. But a high-quality Sativa makes me alert, creative and highly motivated.
Look, everyone is different. What works for me may not work for you. But I wouldn't shy away from it if you think it helps you. Just keep it to yourself and those that you trust and let everyone else judge you by your results.