In its strictest form, Arminianism has taught that man is responsible for saving himself via his own good works of devotion. Although not the view of Arminius, or of Wesley, the teaching from some pulpits puts the emphasis on man's efforts to the expense of God's grace. Thus, in its extreme form, Arminianism leads to the belief that if a believer sins, he has lost his salvation, and must be born again over and over again. Hence, the emphasis in some churches of coming to the altar at each meeting to repent, rededicate, and renew the salvation which was invariably lost in the course of daily life. Adherents of this position have no assurance of salvation, no rest in Christ, and no spiritual peace.
Or, on the other hand, if they can convince themselves that they've reached a state of sinless perfection (which is clearly contrary to 1John 1), then believers become proud and super-spiritual, seeing themselves as having reached a higher spiritual plane than regular Christians. A "works equals righteousness" theology leads either to terror and fear or to pride and haughtiness.
Innumerable believers have lived in needless fear because they wondered time and time again whether or not they were truly saved, thinking that each time they sinned, each time they discovered anything internal unlike Christ, indeed, anytime they felt emotionally separated from God, that they were no longer His children. Surely it is not the will of God for His children to live in such bondage. The fact is that we can know for certain that we are His children, we can know for certain that our sins are forgiven, that we will spend eternity in heaven with the Lord. The Lord does not want His children to doubt His love, nor does He want them to believe that they must, through their own efforts and good works, gain or maintain their salvation. Our position with God is determined by faith in the finished work of Jesus Christ for us on the Cross. We can rest in His love and grace, knowing that He who began a good work in us will complete it. We need not fear the one who said He would never leave us or forsake us, who promised to present those who believe in Christ faultless before His presence, who said that He would be with us until the end of the age.
Similarly, it is not the will of God for His children to feel prideful, for them to take credit for the salvation that is entirely His work, for them to falsely believe that they are sinlessly perfect, or better than other believers in any way. Arminianism has historically lead to the holiness movements which teach sinless perfection, and foster pride in some, while condemning and terrifying the more timid.