One of the hardest things for a product owner to do is say "no" to an enhancement request, but it becomes easier when you can explain that request is at odds with the product vision.
For example, if your product vision is "build the best micro-blogging platform", and you start getting feature requests for full-length blogging (looking at you, Twitter), then it becomes easier to reject those features due to vision misalignment.
If you accept every little request, you have feature blot, and the vision becomes muddled. If left unchecked, you end up with a "do everything" product with poorly implemented, half-baked features spread too thinly.
Experienced product owners realize this anti-pattern exists, and it is easier to sell a product with less features when those features solve the majority of problems for their end users.
Focus on adding feature value, not feature count.