Going to use this chance to vent about the fact that when the senior guy on my team left for another company it was basically all but confirmed I would take over his role I had been there the longest, was already doing a lot of senior work, and was the giy people on the team came to when they needed help, to the point we spent the month or so after he handed in his notice to train me on what he did and give me access to the systems he managed.
Then a week after he left my boss announced that the guy that had been there 3 months would be taking on the senior role.