A recent survey by the European Commission showed that the happiest people in Europe were the Dutch, followed by the Irish and the Belgians.

Older results on Nationmaster gave this ranking :

1) Iceland
2) Netherlands
3) Sweden
4) Denmark
5) Switzerland
6) Ireland
7) Norway
8) United Kingdom
9) Belgium
10) France
11) Finland
12) Austria
13) Poland
14) Spain
15) Italy
16) Portugal
17) Hungary
18) Slovenia
19) Croatia
20) Latvia
21) Estonia
22) Romania
23) Lithuania
24) Slovakia
25) Russia
26) Ukraine
27) Belarus
28) Moldova
29) Bulgaria

Not ranked : Luxembourg, Czech Republic, Malta, Greece, Cyprus, Albania. Macedonia, Serbia, Montenegro, Bosnia-Herzegovina.

The new survey shows that the Irish, and especially the Belgians have become comparatively happier than before. Here is

Expatica : Belgians amongst 'happiest' Europeans

Quote Originally Posted by Expatica
Belgians also rank amongst the biggest consumers of psychological self-help books, but scientists haven't researched into the significance of this relationship.
Relatively, Belgium hospitalises more people for mental health reasons then any other European country. Per capita, there are five times as many patients hospitalised for psychological illness in Belgium than the European average.

In short, Belgians may be crazy but they're happy.