* Missing Subject: The sentence is missing the subject of the verb "make". It should be "Why do we make a party?" or "Why are we making a party?".
* Question Structure: While the words are in the right order, it doesn't sound natural in English to start a question with "why" and then follow with "we". It would be better to invert the subject and verb ("Do we...").
Here are some grammatically correct ways to phrase the sentence:
* Why do we make a party?
* Why are we making a party?
* Why is there a party? (Focuses on the party itself)
* What's the reason for the party?