Time.now # => Returns system time and ignores your configured time zone.
Time.parse("2012-03-02 16:05:37") # => Will assume time string given is in the system's time zone.
Time.strptime(time_string, '%Y-%m-%dT%H:%M:%S%z') # Same problem as with Time#parse.
Date.today # This could be yesterday or tomorrow depending on the machine's time zone.
Date.today.to_time # => # Still not the configured time zone.