Eternal Sunshine is one of my favorites as well. Jim Carrey does an excellent job in that role, I wish he did more serious ones, he's not just a one note comedy actor. All the performances are well done, really, and I think the theme of wanting to forget a person entirely after a rough breakup is one a lot of people can relate to, and the movie explores the price of that in only the way sci Fi can, but it's light, realistic sci Fi, it doesn't come off as cheesy impossible space stuff.