It's the same here with petrol prices but as I don't drive then it doesn't bother me. Only if I'm in a car and the driver pulls in to the garage to fill it up, I then attract the attention of the cashier and point at the prices and make the sign for that's nuts at him or her (generally I get the sign back for f-off in reply)... 
PS:while we're on the subject why do you call it "gas" in the USA, its a liquid, never could get me head round that one...
gas is short for gasoline: From Wikipedia:
Etymology 
A gasoline can (which are typically red) from Midwest Can Company
"Gasoline" is cited (under the spelling "gasolene") from 1865 in the
Oxford English Dictionary.
[1] The trademark
Gasoline was never registered, and eventually became generic in North America and the Philippines.
The word "petrol" has been used in English to refer to raw
petroleum since the sixteenth century.
[1] However, it was first used to refer to the refined fuel in 1892, when it was registered as a trade name by British wholesaler
Carless, Capel & Leonard at the suggestion of
Frederick Richard Simms, as a contraction of 'St. Peter's Oil.'
[2] Carless's competitors used the term "motor spirit" until the 1930s.
[3][4] The
Oxford English Dictionary suggests that this usage may have been inspired by the French
pétrole.
[1] In many countries, gasoline has a colloquial name derived from that of the chemical
benzene (
e.g., German
Benzin). In other countries, especially in those portions of
Latin America where
Spanish predominates (
i.e., most of the region except
Brazil), it has a colloquial name derived from that of the chemical
naphtha (
e.g., Argentine/Uruguaian/Paraguaian
nafta).
[5]. However the standard Spanish word is 'gasolina'.
