Red is fire, red is romance, red is sex. Paint your restaurant red, and people eat more. Red is heat. Red is drive, red is go-getting, red is perhaps *the* most consummate "power color". Even a tiny drop of red in an outfit is what people will look at. Roses and valentines and blood and passion...
People either love to wear red or are somewhat nervous about it. Everyone has a red that they can wear, even something fairly close to "true red". It's a matter of getting the undertone just right. Brick is an autumn tone, geranium or poppy are spring tones, true ruby is winter, and summer wears wine. If you get confused, pair the color in question with colors that you know you can wear. If it clashes, throw it out. Your colors should harmonize, even if they don't "go".
Red is a real eye-draw. You WILL look at red.
Wearing red says "I want attention". Even putting on red lipstick can be a huge thing for a woman, much less wearing a red dress. When you walk into a room wearing red, you are taking control of that room. Red demands it. How many politicians own a wardrobe full of red ties? How many countries' flags incorporate red - red representing the blood of their fallen in battle?
I think that wearing red is something that every woman should try once in a while, and it's possible to wear the more muted reds to get your feet wet. However, no one should force themselves into a bright red dress if that's not where they are - it's a big step. It says, "I'm brave".
I really really want to get that across to my readers (all five of you). Anyone can wear any color that they want to wear, produce any connotation with their outfit. It's a matter of choosing tone, combination, fabric, line... it all goes into the final product. Color is tremendously important, because color makes-or-breaks the outfit at the most basic level. A kindergartener knows if your dress is pretty or not based on its color - and knows whether the dress is wearing you or the other way 'round. Color brings out the best in your skin and your eyes, it makes people respond to you instinctively.
An autumn who can't wear the ruby red that she dreams of can instead wear an equally intense green. Or she can wear a brick red and indulge in red leather accessories. Autumns have an easy time wearing an entire outfit of their red, perhaps because the red is a quieter tone. Springs have a dreadful time finding the bright clear reds that they can wear, but because of their high-contrast blues and turquoises, what red they do find will -pop-. Summers can manage most cold/blue reds - and winter, though she has only a few reds, has the true ruby.
Everyone gets something good, we just don't all get the same good thing.