Science is in the detail. It is the lifeblood of science to discuss.
The current tendency is to go to a meeting with large numbers of participants with numerous parallel sessions and listen to one ten minute talk after the other with only one or two minutes for questions. This information can easily be gained from reading the papers. Only by discussion can you reach understanding.
If one forgot a necessary control, used a poor method, didn't perform the experiment correctly, didn't in fact generate a good experiment, didn't ask the appropriate question, of course you may be afraid of criticism. If on the other hand you are interested in improvement, you should welcome it. Be critical, of your own work, of others (in a polite way), science can only benefit!