Showing you’re annoyed is not the same as making staff scared of you  

Alex Ferguson claims he used his notorious hairdryer treatment no more than 6 or 7 times in his long and successful career. The accounts of former players would indicate it was a lot more but may be the truth is that it was used sparingly in order to maximise its impact. The point is All his players had heard of and probably witnessed one of these fearsome verbal assaults. No one wanted to be the subject of one. 

Showing your staff you’re  annoyed Is not necessarily a bad thing. I worked in the care industry with vulnerable adults and some times I witness or learnt of staff behaving in a callus and cruel way or simply doing what was easiest for them irrespective of the individuals wishes and needs. On such occasions I would make it clear this was totally unacceptable. I may have raised my voice but I never gave the impression I had totally lost control. The aim was not to make people afraid of my displeasure but to realise how unacceptable there behaviour was to me.