The colour white has become synonymous with Wimbledon, and that is mostly thanks to the rather stringent dress code players have to adhere to. According to the official rules, they must wear attire that is almost entirely white - and that does not include off-white or cream. That includes tops, shorts, caps, headbands, shoes, and even any underwear that may be visible. The referee has to approve what the players wear, and can force them to get changed. Roger Federer has called the dress code ridiculous, while Andre Agassi refused to play in the tournament between 1988-1990 largely because of it.