Learn Spanish (Latin America): ¡Quién hubiera aprovechado más la juventud! - If only I had taken advantage of my youth more!

In exclamatory sentences, ¡quién! followed by the subjunctive expresses a strong, often impossible wish for oneself. Even though it literally looks like 'Who had...', it translates to 'If only I had...' or 'I wish I had...'. It is a set phrase used to express regret or a deep longing about your own life.

Why do we use the past perfect subjunctive (hubiera aprovechado) here?

The past perfect subjunctive is used because this is an unfulfillable wish about the past. You can no longer go back and change how much you enjoyed your youth, so it requires this past-tense subjunctive, exactly like in English when we use the past perfect to say 'If only I had taken...'.

Does aprovechar always mean 'to take advantage of' in a negative or manipulative way?

Not at all! While it can mean to take advantage of a person (which is negative), it very commonly means to make the most of a situation, time, or opportunity in a highly positive way. Here, aprovechado just means having made the absolute most of being young.

Why is there a la before juventud when the English translation just says 'youth'?

In Spanish, when you talk about an abstract concept or a noun in a general sense (like youth, love, or time), you must include the definite article (el or la). English usually drops the article in these broad cases, but Spanish requires it.