"Watched this" and "Wanna see" buttons and the purpose of "watchlist" button

I am using "Watchlist" button to mark the movies that I watch. My watchlist is the films I have seen. And I made a second list named "wanna watch" to add the film that I want to see. But it is not obvious that watchlist is a button to mark the movies that you see. I mean I asked a lot of friends and searched the internet. Some people use it as "wanna watch" and others use it as "I saw that one." This has to be clear and a second button like "wanna watch" could be useful. And if you make 2 buttons available on main screens, make people choose how they used "watchlist" button before, make us move out movies to other list if we used it incorrectly. And when I use "Highest Rated IMDb "Top 250" Titles You Haven't Seen" facility, I want to see which ones I have seen too... Btw, I understood that I am using watchlist button correctly after I saw that list. Anyway, thank you.