Since its launch, Huff/Post50 has been interviewing artists, actors and writers. At the end of each conversation, we asked them what is one thing they know now that they wish they knew growing up. Their answers are gems of well-earned wisdom and intelligence. We've compiled a sampling of the Best of What I Know Now and encourage you to comment and/or let us know what's one thing that you know now that you wish you knew growing up. Send your reply with photo to SayItOnHuffPost50@huffingtonpost.com and we'll add it to our slideshow.