In some respects, atheism appears liberating. No God imposing outdated moral values and rules. No confession of sin. No thinking about a distant after-life to affect one's decisions here and now. As long as nobody gets hurt, life can pretty much be tailored to the pursuit of self-interest, with no fear of being judged by an all-powerful Being.
Yet I can't imagine anything as lonely as deliberately living a life separated from the Lord Jesus Christ. Certainly, He makes me uncomfortable when His Holy Spirit exposes sin in my life, and I'm not always thrilled when obeying Him requires me to resist temptation. But I gladly trade my fleshly desires for the joy of knowing Him in this life and (even better) the promise of being face-to-Face with Him for all eternity!