Babies and children need to be allowed to cry.
That is not to say that they need to be left unattended in a darkened room for hours on end! If their crying in distressed, they should immediately given comfort.
However, crying is a baby’s way of expressing themselves whether they are grumpy, frustrated, dissatisfied, annoyed, hungry, tired etc. If you always try to stifle their crying by rocking, feeding or distracting them, they don’t have a chance to release their feelings. They end up storing them up for later, and you have a baby whom you are constantly trying to comfort, or who always has a huge tantrum before they fall asleep. If you can let your baby or child cry until they are ready to stop, they will quickly learn to calm themselves down. While they are crying, it is important to offer them comfort and reassurance, but let them do the calming down themselves.
To understand this a little better, imagine that you have had a horrendous day, when everything has gone wrong and you’re totally fed up by the end of it. When you get home, you may fall into floods of tears, talk your day through with somebody who will listen or you could go for a run. After you have released your feelings you tend to feel more relaxed and happier. If you suppress your anger and frustration, it builds up. Eventually it needs releasing. The same applies to babies and children, but they don’t have words to express themselves so they cry.
As long as the crying doesn’t last too long and reassurance and love is given, it is fine for them to have a bit of a cry.