In the United States, close elections are resolved with a clear winner and a clear loser. Fewer than a 1,000 votes in the final official talley separated Al Gore from George W. Bush in 2000, and the Senate and House were both very evenly divided. Votes cast for Green Party candidate Ralph Nader, in that election, helped George W. Bush win (or, at least, made the race close enough for the U.S. Supreme Court to crown him).
Indeed, in theory, the optimal result for a political party in the United States is to calibrate your positions so that they are just barely moderate enough for your party to control the government by a nose. To obtain a larger mandate you would have to moderate your positions, but would provide no additional ability to pass legislation (unless the support was absolutely overwhelming and permitted your party to pass constitutional amendments).
In Germany, the political system works differently. Inconclusive election results are possible and we have seen one this year. Neither the Christian Democratic Party (a moderate right wing party with 35.2% of the vote) and its planned coalition partner, the Free Democratic Party (think American neo-conservatives with 9.8% of the vote), nor the Social Democratic Party (a moderate party of the left with 34.3% of the vote) and its coalition partner, the Green Party (an ecologically minded left wing party with 8.1% of the vote), secured a majority. Most of the rest of the vote (8.7%) went to the "neo-Communist Left Party" which will also be in parliament. Now, these five parties must horse trade until they arrive at a result which will likely reflect the lack of mandate received by any one party. Unlike Israel, for example, there are no minor players or independents in parliament in Germany to muddy the waters. Votes for parties that receive less than 5% of the vote (which collectively won 3.9% of the vote this year) are discarded, in an effort to reduce the attractiveness of extremists. No new prime minister can be appointed until the five parties in parliament form either a grand coalition or a three party coalition including one of the biggest two parties.
There are four plausible ruling coalitions, even after the voters have spoken. The Christian Democrats, who have ruled out bringing the Left Party into their coalition, need the support of either the Green Party of the Social Democratic Party to rule, either of which would dramatically blunt the impact of the reforms they had hoped to implement. Social Democrats must weight a "grand coalition" with the Christian Democrats, luring the Free Democrats into their coalition, or turning to the left by adding the Left Party to their coalition. Any of these additions would similarly limit the ability of the Social Democrats to implement their program.
One can argue that the uncertainty that flows from a "no mandate" election is a problem, but there is much to like about a system where a close election makes it harder for the winner to implement an agenda, rather than allowing an ideologically narrow group that obtains a paper thin majority to rule decisively.