I'm sure if I went to the future with Doc Brown I'd see I made plenty of decent choices. My life would have turned out well and I'd have no regrets. Doc would warn me not to go to the past and make any changes as it would effect the future and could throw things off more than I could understand. And I'd agree. I wouldn't change anything major.
But if I had some shit-ass children I'd go back in time and warn the past me that heavy Mountain Dew consumption enhances boner strength and makes you more likely to be rich. Then past me would drink it way more, kill my sperm count and I'd never have to worry about lousy children being created.
But if the kids were amazing and musically inclined I'd alert past me to write some more sheet music for the possible family band. Because now it's a reality that WILL HAPPEN. Just gotta make sure we're more ready than the Jackson 5 when that time arrives. Oh and I'd also warn myself about the Puke Seat Incident on that Southwest flight in October of 2012. Just take the first window seat you find. Don't worry about how the surrounding passengers look. As annoying as they appear to potentially be...can't be worse than day old puke.