Decline an Invitation/Request Politely

Draft a polite and professional email declining '[Event Name">[The Invitation/Request, e.g., 'an invitation to speak at the [Event Name] conference', 'a request to take on additional project [Project Name]', 'an offer for the [Job Title] position']'. The email should:
1. Express appreciation for the invitation/offer/request.
2. Clearly state that you are declining.
3. [Optional: Provide a brief, general reason without over-explaining, e.g., 'due to prior commitments', 'after careful consideration, I've decided to pursue a different direction'].
4. Maintain a positive tone and express well wishes if appropriate.