I've been living in dresses for months now. This does take a mental shift. Like you, I used to view dresses as too dressy. I wouldn't even wear them to the office. But something shifted for me. I think it's the fact that I've been able to find dresses that 1) fit (I'm petite and while I can sometimes get away wearing regular sizes in tops and bottoms, I can't with dresses. A dress HAS to be petite or it won't work on me) and 2) don't constrict me in the waist, like pants and skirts can have a tendency to do.
Instead of finding dresses too dressy, now I'm Sylvie's camp and I feel like I'm "cheating" when I wear a dress. Because it's so easy, it's just one piece to throw on. There's little fuss or muss to style it. What's more, I have several dresses that are soooo comfy to wear, it's like going out in your nightgown.
I have been on such a jag with the dresses (starting out last fall/winter) I have built up quite the stable. I am drawn to the dress department first whenever I go shopping online or off. I now have a range of dresses, from casual-enough-for-the-beach, to dressy-enough-for-work.
I even shocked myself recently by falling in love with two maxi dresses (Ann Taylor). Wow. Never thought I'd wear a maxi dress! I've discovered maxi dresses are perfect for backyard parties where there may be mosquitoes, as a change of clothes after a day at the beach, for going to the movies where it is overly air-conditioned.
If I lived in FL, with the weather as hot and humid as it has been, I'd live in dresses the entire time. Dresses (made out of natural, breathable fibers) are so much cooler too.
Embrace the dress!