Worry can be good. It can help a client to prepare for an event, to do their best, to avoid problems. But it can get out of hand, causing confusion and an inability to order thoughts. It can build and become overwhelming. In fact the reasonable, beneficial level of worry is better called concern.
You can worry about
Some of these can be looked at differently. For example there is no point worrying about the past at all, but you can think through past events, learn from them and take action based on this learning.
Worrying about your child’s safety is logical but only up to a point. If your child is 40 and you are worried about his holiday in Spain, this may be overdoing it!
Worrying about your car can again be logical in that it may ensure that you keep it well maintained. If you still worry then this indicates a problem.