EDIT: If you're an expect on child behavior, why are you asking for help? Your kid is 6 months old and is already acting "bratty" according to you so maybe you could be all wrong on this whole punishing your kids until they learn to repress their feelings bit.
Have fun with that one!
Ok...
Your baby insn't able to cope with feelings like you and I can.
What behavior are you trying to stop? Are you trying to stop him from feeling sad and mad or are you trying to teach him to repress it?
Just soothe him and tell him that you will be with him in a moment, or buy him a toy cell phone to let him play with when he wants to play with yours.
Do you think he enjoys this?
Who told you that you're supposed to punish your baby for having negative feelings by making them stop crying before you will show them any care?
Whoever told you that was dead wrong. He might be fed, dry, and not sick but you know, care and comfort is also a need.
EDIT: I had this epiphony when I was trying to deal with toddler tantrums. I had been ignoring them for months and just letting my toddler scream and cry alone to herself. It got so bad that my father-in-law suggested I take it up a knotch and start punishing her for crying for "no reason"
So then I had a fight with my husband that weekend and he made me really mad and sad. I was bawling my eyes out and nobody came. I was crying and crying harder than I had ever cried in a long time and he didn't offer me any comfort and said that he wasn't going to let me manipulate him or make him feel bad and that when I could calm down I could talk to him.
That made me feel so unloved.
Wouldn't anyone feel that way? If you were obviously upset and crying and someone ignored you until you stopped wouldn't that make you feel unloved?
I will never do that to my kids again. When they cry, I comfort them as best I can. I don't give them what they want all the time but I do comfort them when they're crying and tell them that I understand and I will always love them.
I think when you ignore crying and/or punish it you produce screwed up adults like my husband. What kind of a man DOES that? Tells his wife she is being manipulative when she cries? That's just screwed up if you ask me.