You can retire a goal without turning the years spent on it into a waste.

Stopping and having wasted your time are two different things, though the mind runs them together. The years you spent went into skills, friendships, a clearer sense of what you actually want, and a body of work that exists whether or not the goal was reached. Calling all of that a waste is a judgment made from one angle.

If you are setting something down, write out what those years gave you, in plain items, before you decide what the whole thing meant. Tell one person that you have stopped, so it is real rather than unfinished. Then let the next thing start from where you now stand.