Some good advice and a primer on how to get more comfortable with falling...
There is a wonderful feeling of freedom when you can run it out above gear, climbing as hard as you can, totally consumed by the moves. If you don't fear falling, you can enjoy your position, shake out and relax on good holds, clip gear without fumbling and revel in a sense of achievement when you reach the belay. I think we can all agree that we would like to lead near or at our physical limit on well protected trad routes and sport routes.
Some of us can do that, but many of us can't. Most of us operate well within our comfort zone, holding lots in reserve. We may be able to push it right next to protection and can climb above and beyond protection if the moves are easy for us, but once we have to push the envelope we retreat like a gibbering wreck. Holding something in reserve is an essential tactic of course, especially if the protection isn't good and a fall would have nasty consequences, but all too often climbers fail on a well-protected route because they lack the necessary mental strength to climb above protection. Many of us down-climb, grab quickdraws or sit on gear when faced with challenging moves or run-outs.
Often it's not because we can't do the moves but because we are frightened of falling. This doesn't apply to all of us, but it is common.