"I don't bully my staff, but, if I don't shout at them they won't do the job."
Maybe they don't do the job because they have no respect for the manager, because the manager hasn't explained the objectives clearly or because they are frightened of making a mistake and being shouted at more.
A true leader (which is what a manager should be) will instil motivation into his/her staff. Leaders ensure their team is fully briefed, is aware of the objectives and deadlines. They use praise for success to motivate, rather than criticism for mistakes to demotivate. Any necessary criticism is delivered in as positive a manner as possible.
You know your staff feel bullied if :
How to motivate your staff:
Of course, people make mistakes and sometimes more than is acceptable. However, negative feedback should always be given privately and constructively. Tell the person what they are doing wrong and the impact that this is having or may have. Ask them why they think they are making the mistake and how they feel they could rectify it; people will be much more willing to improve if it's their idea.
Watch out for the words "just" and "but" as in "I'm just saying" or "You did a great job but...". Replace the "but" with an "and". "You did a great job and when we sort the parking problem it will be terrific" - so much more motivating.
Use the word "yet"; as in "you've not got it right .... yet".
Finally, I mentioned laughter because I feel it is a vital part of an effective working environment. It relieves stress, builds teams and means your clients are interacting with happy people - what is there to lose?