Girls, what is the sweetest thing a guy has ever done for you?

I like to suprise my girlfriend with little presents or tiny games, or maybe a funny scavenger hunt, I find that it keeps the romantic spark in the relationship. When she went to the gym once, I left a little hershey kiss in her gym bag with a little note taped to it that said "You are the only thing as sweet as chocolate that is healthy :) Have fun working out, I love you." and when she came home she was so delighted :) After that, I decided to do stuff like that more often. One time, she said she would make herself a sandwich for lunch, so I snuck a note that said "I know you're ticklish" in the cupboard where we keep the bread, and when she was reading it, I hid beside the fridge and when she laughed "Oh my god charlie, what is this?" I jumped out and tickled her until she was purple and slapping me lauging. What other things like this could I do?