What were the toughest obstacles you faced while studying civil engineering?

Thank you for invitation..

The biggest  obstacles  which i faced, is to understand all subjects.

The main obstacles is to organize the time .. but I was able to overcome them..thank you

In Mechanical Engineering to complete a highly advance computerized HVAC system.

i guess managing time was the the most difficult task ... for the materials i guess they all required studying and focus and perseverance !

sure i did not remember all , so only Geology 

the most obstacles subject the soil mechanics.