Similarities of French and American election promises

I understand the realities of compromise in politics. But I feel some people are still surprised when their elected candidate conceeds or schemes with the opposition.
For example, the EU decisions do not depend on one country. Mr Sarkozy had to negotiate with a many different countries, with different economic goal and a variety of other priorities. For the French populice to believe Mr Hollande will simply arrive at the soonest summit and have his countries demands met first is unrealistic.

Really? Because every other country is expecting the exact same thing from their newly elected candidate. So the best any one individual can do, and this is in any multi-party representative government mind you, is make policy closely resembling what their constituents want with the fewest concessions to the opponents.

Think Hungry-Hungry Hippo on an international level. Except instead of tiny plastic balls, they are grabbing political clout and policy.

And the candidates play into it, promising to raise taxes on the wealthy to 75% (Hollande) or dismantle social healthcare benefits (Mitt Romney, US presidential candidate). So we the voters place our bets on the dream, thinking if we get enough support the candidate of our choice will be able to meet his promises.
The reality is he or she is just another hippo grabbing at the same amount of pellets. Who are you sending in? And what do you expect them to grab?