Riddle: if you have me you want to share me, but if you share me you no longer have me – what am I?

Introduction / Context:
This question is another classic lateral thinking riddle. It describes something that people are eager to share once they possess it, but once they share it, they no longer have it in the same sense. The wording invites us to think about intangible things that lose their defining quality when they are revealed. Such riddles train abstract thinking and understanding of how meaning changes with context.

Given Data / Assumptions:

• If you have this thing, you feel an urge to share it.
• If you do share it, you are considered not to have it any longer.
• The answer is a single common English noun.
• It is not a physical object but something more conceptual.
• Exactly one option fits these conditions in the traditional riddle sense.

Concept / Approach:
Think about things defined by being hidden or private. A secret fits perfectly: when you have a secret, you often want to tell someone. But once you tell it to others, it is no longer a secret and therefore you do not truly have a secret anymore. The same logic does not apply in the same way to fortune, memory or treasure, which can still belong to you even after being shared or discussed. The riddle is widely known and uses secret as its standard answer.

Step-by-Step Solution:
Consider the word secret. By definition, a secret is information that is kept hidden from others. If you have a secret, it is natural to want to share it with a trusted person. Once you reveal the secret, it is no longer hidden, so you can say you no longer have a secret. Thus secret satisfies both parts of the riddle exactly.

Verification / Alternative check:
Examine the other options. Fortune can be shared, for example by giving money away, but you still have some fortune left or at least you did possess it. Memory can be shared as a story, but you still retain the memory afterwards. Treasure can be shown or divided, but the concept of having treasure does not vanish instantly when it is shared. Only with secret does the act of sharing destroy its defining property, making it the only answer that matches the riddle's logic precisely.

Why Other Options Are Wrong:
Fortune, memory and treasure do not lose their identity simply because they are communicated or shared. You can talk about your fortune and still have it, recall a memory and still remember, or present treasure and still possess it. Therefore they do not fit the condition that sharing causes you to no longer have the thing. They are included as plausible sounding but logically incorrect distractors.

Common Pitfalls:
Solvers sometimes look for deep philosophical interpretations of sharing rather than noticing the straightforward definition of a secret. Another mistake is to think of sharing in a purely financial sense and focus on fortune. In many riddles, the key is to identify the one word whose very definition collapses when the described action is taken. Recognizing that secrets cease to be secrets when revealed is the insight that unlocks this puzzle.

Final Answer:
The answer to the riddle is a secret.