Is devotion in prayer merely a psychological feeling, or is it a connection between the servant and his Lord, and how do non-Muslims feel it?

The soundness of a religion is not evidenced by spiritual pleasure or the feeling accompanying acts of worship, for this is the true fruit of faith and not its foundation. The proof of a religion's soundness lies in sound revelation and a sound intellect. Indeed, disbelievers may find pleasure in worshipping their deities, which have been adorned for them by Satan. Furthermore, khushu' (devotion/humility) in Islam is the submission of the heart and limbs to Allah, differing from the worship of other religions that lack the true reasons for khushu'. Whereas the prayer of Muslims, filled with khushu', deters from indecency and evil. To achieve the pleasure of faith, one must attain true faith through love for Allah and His Messenger, complete adherence to the Prophet, peace be upon him, and consistent performance of good deeds. A Muslim must turn to Allah in supplication, asking for guidance and steadfastness, and occupy himself with beneficial Islamic knowledge.