I was very worried too when first diagnosed.... but the real dangers are, like Zoe said,
neuropathy in your feet that causes loss of feeling, and poor circulation in the feet.
The loss of feeling means you may not notice an injury and it may fester for a long time and get infected. Your endocrinologist should test the feeling in your feet on every visit to make sure you are not losing sensation. He/she does this by brushing your feet with a little whisker like a broom straw and asking if you can feel it . Another test is they hold a vibrating tuning fork on your foot and ask you to say when you stop feeling it vibrate.
Peripheral vascular disease - poor circulation in the extremeties - is another cause of foot problems. Poorly controlled blood glucose causes damage to the small blood vessels all over your body. This is the source of many diabetic complications including retinopathy, kidney disease, etc. In the case of the feet, poor circulation can lead to poor healing, increasing the chance of serious complications when you are injured. The poor circulation is also a cause of neuropathy. Your endo or podiatrist may also periodically check your "pedal pulses" (foot pulses) to check the circulation in your feet. Another test they do is to press briefly on the skin of the foot. It will turn white as the blood is squeezed out, but then should turn pink again quickly (within about 2 seconds) as blood flows in to the capillaries.
The best thing you can do to avoid these problems is to maintain good control
of your blood sugar. Inspecting your feet nightly is a good habit and protecting them.
The circulatory and neuropathy complications that lead to foot problems take long periods (years) of poor control to develop, so it is not something that will happen right away (or even at all if you keep good control).