1 - Rapunzel spent her time bettering herself.
Rapunzel was stuck in a tower, but rather than spend all her day on facebook or watching stupid reality TV shows (Kardashians...cough cough ZOE;), she read books, painted, cooked, and all around used her time well. Sure, she was waiting for her "life to begin," but she wasn't lazy.
2 - Rapunzel dreamed and inspired others to do the same.
Enough said? Rapunzel knew what she wanted, so she chased it. She helped Eugene realize what he wanted, and at the end of the movie, he said that people were achieving their dreams all over the place because of her.
3- Flynn (Eugene) and Rapunzel didn't fall in love at first sight.
People don't fall in love at first sight. I apologize if that's how you thought it happened. Even when they did fall in love, it was a few years before they were finally married. On top of it all, Eugene said she was a princess worth waiting for:)