Here’s something I learned the hard way (by messing up, of course!)
If you are ever critiquing someones work at their desk DON’T ever do a reach around (no, not the one that will send you to HR, but don’t do that either).
What I mean is never reach around the artist and grab the mouse, stylus, pencil, keyboard, or whatever it is they are using to create without always asking first. Even then, be aware of what you are doing and how often you are doing this type of action. When you reach around and grab the mouse (for instance) you are essentially taking control away from the artist, and sending a message that they don’t know what they are doing and you need to do it for them. Animation is way too collaborative of a medium for any of us to do it alone. We need to work together, and you want everyone to feel like they are both contributing and that they have some level of ownership.
Rather than reach around and take over for the artist, try to explain what you want in a way they can understand and then execute. It will not only let the artist retain a sense of ownership, but it is a great lesson for you as a lead/director in how to explain yourself so others can understand what you want.