I have once heard someone say that he would rather regret for what he has done than for what he did not do. That attitude impressed me and called my attention to watch out opportunities and act whenever possible.
Today I read a quote by Sidney J. Harris and found the marvelous explanation for why we should always choose to act than to vacillate.
Regret for the things you did can be tempered by time; it is regret for the things you did not do that is inconsolable.
Do all the things you want to do. There is only one life and you won’t ever want to regret for the things you did not do.