I can guess that Prophet Muhammad (PBUH) liked the green colour because:
The prophets faviroute coulour is green because it is the coulour of nature and the first man to wear it was prophet muhammad.
The color green is strongly associated with Islam and is considered to be the favorite color of the Prophet Muhammad (PBUH). It symbolizes nature, life, and paradise in Islamic culture. The green dome of the Prophet's Mosque in Medina is believed to be painted green to honor the Prophet and his love for the color green.
There is no Islam symbol, per Islam religion, to know its color. However, green color is the one used by prophet Muhammad (PBUH). refer to related question below.
Suwayd narrated that Anas said, "The most beloved colour to the Messenger of Allaah (sallallaahu 'alayhe wa sallam) was GREEN."
It is the Prophet's favourite color.
Some countries where the color green is considered sacred include Ireland, where it is associated with luck and prosperity; Iran, where it symbolizes Islam and nature; and Saudi Arabia, where it is associated with the Islamic faith and the Prophet Muhammad.
Well, Saudi Arabia is the reference for almost more than 80% of Islamic population and the green color was the color of early Muslims therefore, the green was chosen to be the dominant color in the flag
I don't believe God (swt) has a favourite color, He doesen't think like us humans. Perhaps He likes all colors equally? Prophet Muhammad's (pbuh) favourite color is green though. I've also heard he liked white. It is also told that in Heaven, people will wear green garments.
Well, the Prophet (PBUH) and his caravan used to carry (generally) solid black, green, or white flags. Green was the colour worn by the Prophet Muhammad (SAW). So Green is most preferable. In addition to green, which symbolizes growth and flourishing (especially in a desert), the other colors of Islam are: red, white, and black. It is not surprising, therefore, that most Muslim countries use these colors exclusively on their flags.
The color red has no particular meaning in Islam. The color green is often considered symbolic of Islam, as it is one of the colors of heaven. The flag of Prophet Muhammad (God bless him and grant him peace) was a plain green field. Deceased Muslims are usually shrouded in white, because a plain white cloth is the least expensive, and it is forbidden for Muslims to spend large sums of money on burials. Male Muslims who perform the pilgrimmage to Makkah wear simple white cloths instead of sewn clothing. In some Muslim countries, widows wear white, but that is cultural, and has no basis in the religion of Islam.
These are called preferred channel markers. Which means you can pass on either side, however whatever color the topmost color is is the preferred passing side. Topmost Green prefer to pass on Starboard (right) Topmost Red prefer to past on Port (left). There are sometimes lit, sometimes lettered, never numbered.
According to an article posted on "The Onion," in July, 1996 Muhammad Ali stated that his favorite color as "Yellow" because "It is a very pretty color. It reminds me of daffodils in the springtime." The article cited can be seen in the related link.Previous to 1996, he stated that his favorite color was black.According to CBS news, Muhammad Ali's favourite colour was black, due to some sort of religion.- Tristess131