Why US fears gas price over 5$ a gallon when its cheap compared to other countires?

US avg salary is about 50% higher than other countries, and the cost of living there is much cheaper, also 5$ a gallon is around 50% cheaper than lots of other countries where people earn much less on avg.

So why it matters so much to US if people in other countries that make less money than US would consider 5$ a gallon cheap?