Your 20s are a time for figuring out what you want from life. Mistakes are unavoidable, but the truly successful learn from these setbacks and move on all the wiser. We asked entrepreneurs, including a few "Shark Tank" investors and the cofounders of popular retailer Warby Parker, to share the most important lesson they learned in their 20s. Here's what they said. Read more: Best lessons entrepreneurs learned in their 20s - Business Insider A very interesting read.