Why is it, if it's not Valentine's Day or her birthday/anniversary, flowers are an I Screwed Up gift? A guy with flowers during a non holiday seems to be a guy with his head hung low, who screwed up with his girl and needs to apologize.
Most guys never think about giving their girl flowers otherwise. In fact, if you want to make a big bang with your gal, the best thing to do is pick a random day, and have flowers sent To Her Work, because all the other women will notice a delivery of flowers with a "just because you're you" note on them, and talk about it amoung themselves, saying...my boyfriend/husband has never done that, she must have some guy!