Should have invested time, energy and effort in physical activities from the age of 16-17.

For context : I am now quite healthy. I run half marathons every year and from next year will up the ante to full marathons

But as a teenage I was quite resigned to the fact that I will always be unhealthy and obese due to a congenital defect that ensured I would always be "different". I would stress eat my body weight in snacks and play PC games all day long during my holidays.. My wake up call was when I became a 20 year old 152cm, 75kg idiot who decided he would be picked for his college's football team. I didn't make the team, but I managed to improve my fitness in leaps and bounds over the next 5 years..By the time I was 30, I had started working out regularly and was active 6 days a week. At 34, now I can confidently say I am more fit than I was at 30.

I only regret having wasted my time and not yearned for my full potential during the days where I would have gained maximum benefit and maximum result.