What you perceive as "dressed up" might be somebody else's supremely relaxed and casual. In the summer I prefer to wear dresses because they're light, no fuss, and comfortable. Does that mean I'm being fancy? Hardly! The dresses I buy are typically no-wrinkle, wicking fabrics that can be worn multiple times before washing, like this one, which I'm wearing right now. Comfort and ease don't mean you have to look like a slob or have no style.