You are probably going to think this is the stupidest thing you've ever heard. Please... hear me out.

A number of scientific studies have found that there is a human bias towards people wearing red clothing.

Red enhances human performance in contests, Russell A. Hill & Robert A. Barton, Nature 435, 293 (19 May 2005):

Red coloration is a sexually selected, testosterone-dependent signal of male quality in a variety of animals, and in some non-human species a male's dominance can be experimentally increased by attaching artificial red stimuli. Here we show that a similar effect can influence the outcome of physical contests in humans — across a range of sports, we find that wearing red is consistently associated with a higher probability of winning. These results indicate not only that sexual selection may have influenced the evolution of human response to colours, but also that the colour of sportswear needs to be taken into account to ensure a level playing field in sport.

They looked at some Olympic events where competitors were randomly assigned blue or red outfits. They found the competitors wearing red won 60% of the time (provided the competitors were equally matched before hand.)

Attrill, Martin J., Karen A. Gresty, Russell A. Hill and Robert A. Barton. 2008. Red shirt colour is associated with long-term team success in English football. Journal of Sports Sciences. 26(6):577-582:

Since 1947, English football teams wearing red shirts have been champions more often than expected on the basis of the proportion of clubs playing in red. To investigate whether this indicates an enhancement of long-term performance in red-wearing teams, we analysed the relative league positions of teams wearing different hues. Across all league divisions, red teams had the best home record, with significant differences in both percentage of maximum points achieved and mean position in the home league table. The effects were not due simply to a difference between teams playing in a colour and those playing in a predominantly white uniform, as the latter performed better than teams in yellow hues. No significant differences were found for performance in matches away from home, when teams commonly do not wear their “home” colours. A matched-pairs analysis of red and non-red wearing teams in eight English cities shows significantly better performance of red teams over a 55-year period.

Hagemann et al. When the referee sees red, Psychological Science, Volume 19, Issue 8, Date: August 2008, Pages: 769-771:

we conducted a new experiment and found that referees assign more points to tae kwon do competitors dressed in red than to those dressed in blue, even when the performance of the competitors is identical.

Here they did a controlled experiment by digitally altering a video of tae kwon do competitors.

Women wearing red are found to be more attractive by men, http://www.rochester.edu/news/show.php?id=3268 :

Research has shown that nonhuman male primates are particularly attracted to females displaying red. Female baboons and chimpanzees, for example, redden conspicuously when nearing ovulation, sending a clear sexual signal designed to attract males....

Under all of the conditions, the women shown framed by or wearing red were rated significantly more attractive and sexually desirable by men than the exact same women shown with other colors. When wearing red, the woman was also more likely to score an invitation to the prom and to be treated to a more expensive outing.

https://www.newscientist.com/article/mg20327232.400-winners-wear-red-how-colour-twists-your-mind/ :

Mandrills, the world’s largest species of monkey, use colour as a means of conflict management. In males, red faces, rumps and genitalia act as a status symbol, communicating fighting ability. “The brighter red a male is, the higher his testosterone level and the more aggressive he is,” … Other primates use more subtle variations in facial redness to signal dominance. Rhesus monkeys, for example, become redder in the face in the mating season.

EDIT: More Links:

https://medicalxpress.com/news/2017-02-people-outward-health-actual.html

People who eat lots of carrots develop skin with redder pigment, are found to be 50% more attractive!!:

Results found that, as predicted, beta-carotene supplements increased overall yellowness and redness but not lightness. Post supplement faces were 50% more likely to be chosen as attractive as well as healthier looking compared to the pre-photographs or the placebo group. Thus beta-carotene supplement significantly enhanced participants' attractiveness and appearance of health.