the gemara has a full sugya on dreams in brachos 55a to 57b. a good dream is one of three things that need rachamim (55a). a dream uninterpreted is like a letter unread, and a person troubled by a dream should do hatavas chalom, improving it before three people (55b). and shabbos 11a says יפה תענית לחלום כאש לנעורת, a fast works on a bad dream like fire on chaff, ideally the same day, and even on shabbos.

1. does any of this still apply? if someone has a disturbing dream, are hatavas chalom or a taanis chalom actually prescribed or practiced today, or did the poskim quietly drop the whole thing?

2. do dreams carry real meaning at all in halacha and hashkafa? the same sugya says a person is only shown מהרהורי לבו, the thoughts of his heart from that day (55b), so is the working assumption that dreams are just the day’s residue?

3. and if chazal themselves said אין חלום בלא דברים בטלים, no dream is without nonsense (55a), why did they take dreams seriously enough to build practices around them?