Why can’t spiritual path be smooth and comfortable?

Of course there is a sweet and sunlit path. In fact they advocate this sunlit path for all. But very few are able to walk upon it. It requires absolute faith and complete surrender as well as an increasing sincerity. If one has that and keeps to it through whatever ups and downs yet may come, then one is well on the royal road to the Divine. But wanting yoga so that one has no outer difficulties indicates a mixture in motive. To seek the Divine only to save oneself from difficulties is an inferior form of bhakti. One can take that route but it means the time taken will be long. Besides, as such, one cannot avoid certain difficulties in life. They arise from the very nature of life and our attachments and desires. And these things bring a certain degree of suffering regardless of path or no path. The difference however is that those sincerely turned towards the Divine go through them in a relatively unaffected way while others often get submerged by them.