Separation anxiety can be hard on everyone, not just the child. Parents are often the ones who suffer the most. The problem is that separation anxiety is a normal stage children go through.
A typical 10-month-old will all of a sudden start to cry when dropped off by parents. This baby may have been in your care for almost his whole life, been dropped-off with no issues, then start to show anxiety out of the blue. It's because this is a natural stage babies at this age go through.