Regret is looking back and realizing that you spent or wasted your time doing the wrong things or investing it on the wrong ventures.
Regret usually occurs when people fail to evaluate how they have been spending their time and resources and what they are spending it on. Your greatest asset in life is your Time and when this is spent wrongly there's no way of getting it back. If you lose your job, you can get another job, if you lose your money, you can work for another, if you lose your wife/husband/kids, you can get another, if you lose your properties, you can get another etc, but if you lose your time, there's no way for you to get it back - though you may be able to make up for it by trying to utilize the time you have left wisely.
But the sad thing is that most people hardly make up for their lost time because they hardly sit down to evaluate the outcomes of their spent time. Our present world and everything in it is moving so fast that no one wants to wait for anyone or be left out. Everyone is so busy that no one is ready to slow down and take stuck on what he/she is "busying on".
Our daily lives have become a routine but most of us are unconscious of it and striving to get a different and better outcome from what our routine life is getting us. And we sometimes wonder why things aren't getting better for us despite our hardwork and very busy schedules.
We fail to see the circular motion of our lives because we care too much about just doing something and getting things moving, rather than doing something that counts and getting things moving in the right direction. Some of us would realize when it's too late or when there's just little time left and there's nothing much we can do that we've wasted the most of our precious time and energy just getting busy doing the wrong things and regret and depression may creep in because we fail to sit down when we had the time to evaluate what we've spent/spending our precious time on.
Listen, life is not a competition and every man isn't going to the same destination, so it would do you no good to join others in the rush because of the fear of being left out. The question is "where are you rushing to?" Are you going to the right destination and do you know what you're going to do in the destination you're going to?It's not enough to do something, are you doing the right thing? I don't think it is too late for you to make a U-tune if you're on the wrong path. I also don't think it's too late for you to stop and ask yourself "what do i want? And am I on the right path and doing the right things that would produce for me what i want?"
The quality of the life you'll live or are living is a product of the outcome of your time. If your life is not as quality as you want it, you can apply the brake of the vehicle of your life right now and start evaluating your journey thus far. It's not too late to have a rethink and an evaluation of your life's journey thus far so that you can avoid the regret that may be lurking around the corner to hit those that failed to step on the break of the vehicle of their life to re-evaluate their life's journey. The ball is in your court!