What scenario would be worse:
Staying friends with an X-crush* or crushing on a friend?
*A person you wanted to be in a romantic relationship with at one point, but not anymore. You may still be attracted to them however.
Staying friends with an X-crush Pros
That friend may get a sort of special treatment from you.
You can/will become especially close to them.
You are motivated to please them, even be like them. If they are good then that can be good for you.
They will always have a special place in your rank of friends.
You will likely know them on a higher level then general friends.
Staying friends with an X-crush Cons
If you are still attracted to them you may interpret actions incorrectly.
You are setting yourself up for continual sadness in not getting a desire fulfilled.
You may have tension in the friendship, maybe it's only felt in your head though.
If you get into a new relationship, your partner must accepted the friendship you have with the X-crush. Not everyone is so trusting.
You must guard yourself not to fall into dark thoughts about the person; you know it will never happen.
Crushing on a friend Pros
There is motivation to get to know them well.
You will want to stay on their good side.
Time with them is especially enjoyed.
When you compliment them, you mean it.
If you are ignorant to your full emotions concerning them, you enjoy the special closeness without the complications of a secret crush.
Crushing on a friend Cons
You will struggle with the secret unless you tell, or until it somehow melts away. Though even then it will still be an old secret.
You may get obsessed with them.
They will have unequal treatment from you compared to general friends.
They may have a certain control over you, like how your decision making is influenced.
You might make choices to please them rather than yourself.
You will always feel like there is something "missing" in the relationship.