It's just something I learned in my psychology class during college when we were talking about the psychological impacts of colors on the subconscious.
Here are some other facts on yellow:
-Yellow is a bright that is often described as cheery and warm.
-Yellow is also the most fatiguing to the eye due to the high amount of light that is reflected. Using yellow as a background on paper or computer monitors can lead to eyestrain or vision loss in extreme cases.
-Yellow can also create feelings of frustration and anger, as mentioned above. While it is considered a cheerful color, people are more likely to lose their tempers in yellow rooms and babies tend to cry more in yellow rooms.
-Yellow can also increase the metabolism.
-Since yellow is the most visible color, it is also the most attention-getting color. Yellow can be used in small amount to draw notice, such as on traffic sign or advertisements.
But I think we're getting off topic here, I'm sure the Google-Mobile can tell you just as well.