Is Joel Osteen teaching a false doctrine?

the claim you make there is unsubstantiated. Christians indeed do not worship the same God as mulsims and hindus, for example. religion says you are saved by what you do, a works-based righteousness and salvation mentality. the gospel teaches otherwise, the gospel says that we are broken sinners saved by God's grace through faith in who Jesus is and what he has done. Jesus lived the perfect life tempted yet without sin, he died in our place for the punishment of our sin and rose to conquer Satan, sin and death and give us new life. In no way, I stress, in no way do Christians worship the same God as the world religions. There is but one God, the Trinitarian God of the Bible - Father, Son and Spirit and in Him and Him alone life, salvation and truth is found.

Now to go onto what you said about the Catholic church, creating faith by making someone feel guilty about what they have done is not faith at all. Real faith is belief in the God of the Bible knowing that we are not saved by what we do but by what Christ has done. 1 John says 'perfect love casts out all fear' God has perfect love for us and if we have faith in Jesus we need not fear eternal torment as John 3:16 says that 'anyone who believes in Him (Jesus) shall not perish but have eternal life'. If fire wrath and brimstone are not accompanied by a conviction of the Holy Spirit the hearers will be left feeling guilty, when what really should lead us to repentance is God's love demonstrated in the life death burial resurrection and ascension of His Son.

Joel Osteen is a heretic, a false teacher and I would even go as far as to say believes in a different god. His idea of the God of the Bible is unbiblical. He says that if you believe in Jesus you will have a great and victorious life and God will make you rich. That teaching is outrageously absurd, he claims it to be the gospel, which it is clearly not. The Gospel can be summed up in this: we are broken, sinful and destined for Hell, God in His love came into his own creation lived perfectly died for our sin and rose to conquer the power of satan sin and death and he will return in his time to judge the living and the dead and usher in the New Creation with a New Heaven and New Earth. Anything other than that is a false gospel, and according to scripture, is inspired by Satan and demons.

So, his teaching begs this question, is there something wrong with a Christian who is poor? An accepted tenet of the Christian faith is that Jesus is our example, in Osteen's eyes he would probably say something like Jesus didn't have enough faith which is just utterly idiocy. Essentially, Osteen says, the more faith you have in Jesus, the less you have to be like him, which is just ludicrous because Romans 8:29 would have us believe that we were predestined to be conformed to the image of His(God's) Son (Jesus). Come on, Christians do worship a homeless Galilaean peasant who had to do the backbreaking work of capentry until he was baptised by the Holy Spirit upon which time he started living in houses at which people would let him stay.

And you ask why so many people go to his church? His teachings demonstrate a subtle idolatry that rather than desiring God above all else they desire a better and more wealthy life by disguising it with so called faith.