Really frustrating is when business asks you to finish large tasks in an unreasonable amount of time (4-8 hours). As a Medior developer, my speed is not at hours, but at days/weeks. Perhaps if I were a Senior with absolute mastery I could achieve such speeds.

They don't seem to understand programming takes a lot of thinking, testing, debugging and communicating, which not always necessarily sync. Some people are busy and others are jerks.