The way I always have understood it is to blaspheme against God to
someone else, particularly someone who is still lost. Because then you are purposefully leading someone away from God who may never again cross paths with a Christian.
I think that when you are yelling at God for the troubles in life, you are closer to Him than when everything is going great. You are acknowledging Him and are in fellowship with Him.
I definitely agree with Lynne on this part. I know that at one point in my life when everything was at the absolute lowest point - and I was even beginning to question my faith, I was in my car on the way top pick up my son (the one with Asperger's) from his school for getting into yet another fight. I just started squalling and yelling out loud at God things like "why do you keep doing this to us? haven't we been through enough? etc, etc." (basically whining) - but I came to the sudden realization that I could not possibly be THAT angry and hurt with someone that I did not
believe in. Also, you can't be hurt by someone you don't care about - so obviously, God still meant a great deal in my life, and I wasn't ready to give up, yet.
but I did need Him to hit me over the head to realize it!