Gideon blames God for his troubles and the troubles of his nation because he makes an error in logic--that if God is with one, no harm or evil may befall that one. However, God has not promised us a Disneyland, as Campus Life magazine used to point out. And it is also necessary to define "harm or evil," as God views those things from His perspective: if something brings discomfort but results in glory to our God, He may be quite willing to permit it to proceed.
Gideon's assessment is not accurate, because God had not abandoned the Israelites. He had temporarily given them into the hands of the Midianites because He loved them and chastened them, but He was still with them.
We blame God because we want things to go "well" for us or other people, but we judge what is "well" from our own perspective. We want things our way.
The danger in blaming God is not in bringing down His fierce judgement and revenge, but in permitting a seed of bitterness to take root in our heart. Then, the enemy can water that seed, and everything "bad" which happens to us will "prove the validity" of our harbored assessment of God: that He doesn't love us anymore, has left us, and is bent on our destruction. We are then caught in the lie of the serpent in Eden--God does not have your best interests in mind, which in turn gives us license to sin. We stray or run further from God, He allows us (in love) to suffer the consequences of our sin, and we (suffering more) judge God as our enemy.
To avoid this downward spiral, we must refuse to allow that seed of bitterness against God to come into our heart. Throw it out, quick! As we go through trials of our faith, and insist on trusting Him and declaring to Him our faith in His love for us, we grow in our ability to accept "bad" things as good when they come from His hand.