At first crying is the only possibility for babies to communicate their discomfort. They have no other choice as they can not talk to you. The crying is a helpful indicator for parents, who wouldn't know otherwise when to take action. Often the type of crying can tell a lot about the cause (distinguishing the type is something you learn while parenting, in the meanwhile you try things on random until the crying stops). Crying out of pain sounds very different than crying because of a full diaper. So for the first 2 years, this is definitely a really helpful thing. It might be annoying, but that is an advantage for the child as it pushes you more to do something about it.
As the child gains more abilities in communication, the crying will decrease. But it will still be used as one important instance of communication. You will also be able to distinguish crying that has important reasons (like pain) from crying e.g. out of frustration where the child just has to go through at times. It depends on your reactions and the character of the child how much she will use crying or replaces crying with other types of communication. E.g. one year olds will use their fingers to point at things they want. So did my son point at the bottle or the mug if he wanted something to drink. If you recognize this and react to it appropriately, the child will be more likely to use the finger pointing instead of crying to ask for water.
Once the child's ability to talk increases she has even more ways of telling you what she wants. But she still doesn't know how to deal with frustration, with not having control over the whole world. The age where children throw tantrums is also known as the terrible twos. The child still needs to learn how to deal with her emotions and you can help her with that by showing her ways and by being a good role model. Don't reward this kind of crying, meaning: do not retreat to avoid tamtrums and the child will not use it as a way to get what she wants (nevertheless she still needs to learn how to deal with frustration). Temper tantrums are common in the age of 1 to 4 years and most children grow out of it.
Besides that: The ability to talk doesn't mean that the child is able to reflect on the reasons of his discomfort. Meaning: He might have the words to tell you: "Dad, play with me. You are always distracted with being online and answering questions on StackExchange. That makes me upset."
But he might not be able to realize that this is the reason he is upset, so he just cries.
To sum it up: See crying as something useful, as a way of communication. You influence how much the child has to rely on this form of communication when she gets older.
