Using 'dressy' can imply you're wearing something too fancy for an occasion, potentially making you stand out. He realized his dressy attire was too much for a simple dinner out.
Pro Tip 2/3
Style Excess
'Dressy' often suggests effort put into appearance, possibly hinting at vanity when misused. Her dressy look seemed to seek attention at the casual gathering.
Pro Tip 3/3
Casual Contrast
'Dressy' can create a strong visual contrast when used in casually-dressed settings. His dressy shirt was in stark contrast to the sea of t-shirts around him.