In training missed lifts should be minimized. The goal of training is to reinforce perfect technique. Missing lifts teaching you how to miss more lifts.
But as lifters progress, occasional misses are part of training. Here are some reasons for misses and moving forward from them. I see three primary reason for a missing lifts.
- Technique (lost back/core tension, not patient, not reaching full extension, etc.)
- Confidence (scared to get under, not aggressive enough in pull or drive)
- Weight to Heavy (weight is simply too heavy for the given day)
For technical errors, correct it on the next lift and move forward - always focus on the positive to cue AKA what to do, not what to avoid. If confidence is issue come back to the bar only when you know you will make the lift. Make use of positive visualization techniques before lifting. Visualize yourself making the lift in your head before approaching the bar.
Sometimes for technique and confidence issues it may be useful to bring the weight down and wave back up.
Sometimes the weight is simply too heavy for the day and adjustments need to be made to the expected intensities for the day.