Chicago's Ohare customs was inefficient to say the least. As I was arriving from MX, not a hot spot, there were thousands of people backed up in customs with no explanations, time frames. Shameful. Clearly all they needed to do was communicate and make appropriate lines for those returning from Mexico, those from Europe, ect. Again, no explanations or communication. Also, American airlines should have distributed customs forms to us so we can properly fill them out vs standing in a line writing on each others backs.