1. Not traveling when you had the chance. Traveling becomes infinitely harder the older you get, especially if you have a family and need to pay the way for three-plus people instead of just yourself. 2. Not learning another language. You’ll kick yourself when you realize you took three years of language in high school and remember none of it. 3. Staying in a bad relationship. No one who ever gets out of a bad relationship looks back without wishing they made the move sooner. 4. Forgoing sunscreen. Wrinkles, moles, and skin cancer can largely be avoided if you protect yourself. You…