By about a month, you will probably begin to see a rhythm in your relationship with your baby. Some of your life together is predictable - you know that he or she will wake three or four times a night, and they will know that when they do so, you will feed them.
Whether you are calm or anxious, quiet or chatty, your baby will expect this of you. Babies also have their own temperaments and by now you'll be learning how your personalities 'fit'. If you do something your baby doesn't expect, he or she will become worried or cry. In experiments, babies whose normally smiley mothers responded blankly to them, got very upset and cried because their expectations had been shattered.
When you talk to, or feed, your baby he or she will gaze at you, gradually looking more alert. They will focus on your face because it's curvy, it moves and has areas of high contrast. Babies love all these things. It's also about 20cm away, the distance at which he or she can focus best. Your face is their gateway into the social world and from it they will learn about smiling, talking and emotions.
It is also a mirror of their importance. It's hard to keep your true feelings from your baby. If you can't love your baby straight away (and not every parent can), don't hide behind a big smile - your baby will see through it and the mixed message of looking happy and feeling sad will confuse them. Better to be honest with your baby and yourself. If your lack of loving is a problem for you, talk it through with a good listener or talk to your baby about it - their response may bring you closer.