Based on the search results, there are several primary factors that drive a nation's imperial ambitions:

1. Economic motivations:

   • Desire for new markets to sell manufactured goods123
   • Access to raw materials and natural resources12
   • Expansion of trade routes and economic influence12
   • Pressure from business interests seeking overseas investments and profits23

2. Strategic and political factors:

   • Acquiring overseas territories and military bases28
   • Competing with other imperial powers for global influence28
   • Expanding political control and power on the world stage13
   • National security concerns and geopolitical rivalries38

3. Ideological and cultural factors:

   • Belief in cultural/racial superiority and "civilizing mission"134
   • Nationalism and national pride24
   • Spreading religion (e.g. Christianity)1
   • American exceptionalism in the case of U.S. imperialism5

4. Military motivations:

   • Demonstrating military might1
   • Acquiring strategic bases and ports28
   • Expanding naval power and influence8

5. Social/domestic factors:

   • Distracting from domestic problems5
   • Belief in Social Darwinism and racial theories7
   • Humanitarian motives to "improve" other societies1

6. Technological advances:

   • Industrial Revolution enabling expansion of imperial reach3
   • Improvements in transportation and communication3

The search results indicate that imperial ambitions were typically driven by a complex interplay of these economic, political, ideological, and strategic factors, rather than any single motivation. The specific balance of factors could vary between different imperial powers and time periods.