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This weekend, Jim Carrey gave the commencement speech at a small university in Iowa, doing a variation on the "follow your passion" speech. Even if you fail at what you love, he said, you'll have fewer regrets than if you fail at the thing you weren't passionate about.
Mac Andreessen disagrees. In his latest series of Tweets, Andreessen explained why following your passions is a terrible idea. 
Too often, people follow their passions into fields that are simply too competitive for where their skills are in those things.
Instead, Andreessen believes one should "do what contributes" — follow the thing that provides the most value to others.
Check it out:
Andreessen isn't the first to reject "follow your passion." Two years ago Marc Cuban suggested you should "follow your effort." There's also the classic, "don't do what you love, love what you do." And still others have suggested a more complicated if more realistic calculus of doing what you're good at so long as it gives you some satisfaction.
The consensus best commencement speech of the season still appears to be the one delivered by Adm. William McRaven, the head of U.S. special operations, at the University of Texas.
His advice: You can't follow anything until you've made your bed. 
Disclosure: Marc Andreessen is an investor in Business Insider.