You can find almost anything in the Firefox configurations page.
For smooth scroll
1. Type about:config in the address bar in a new tab.
2. Click on the warning I'll be careful, I promise!
3. Type smooth in the filter bar.
4. Double click general.smoothScroll. This changes it value from false to true.
For smooth clicks
1. Type dom.ipc.plugins.enabled in the filter bar.
2. Set the value to true by double clicking on the name.
3. Restart the browser for both the effects to take place.