Some Christians have the mistaken idea that God saved us and then gave us this impossible model of a life we should live and then left us all alone to try and live it. Apparently, they think God is sitting in Heaven twiddling His thumbs while we muddle through down here the best way we can! These are the same people who are always making it hard on themselves thinking that by suffering through life everyday they will please God. That's not what God meant when He said to "deny yourself"!
The Bible says that "He who has begun a good work in you" will finish it. God has begun a good work in us and He will finish it! The Bible also says that it is God who gives us the ability to "will and to do". God isn't only working in us to give us the ability to do what He says, but it is He who gives us the very "want to" to obey Him! God isn't sitting by in Heaven while we mutter through. He is personally and constantly working in us and through us by the Holy Spirt! We are not alone! God didn't ask us to fly and then deny us wings! We must have faith in God. We must believe that He is able to make of us whatever He wants us to be!
I'm not saying that we can live any old way we want to and God will be pleased with us. Neither am I saying that we don't have to say no to evil desires and yes to the Holy Spirit's promptings. But beating ourselves up and making ourselves miserable all the time are just works of the flesh; they are religious ideas trying to impress God with our self-inflicted sufferings. The Bible says that the flesh has works but the spirit has fruit! The flesh works hard to get anything done, but have you ever seen an apple tree straining to put forth apples? No!
God won't leave us the way He found us. He will always move us toward perfection. All we have to do is trust and believe and stay out of His way.