All the superbly confident people that you see around you did not have this by chance.
Confidence is a skill, that could be developed with practice and when not practiced, loses its edge.
So here is the good news: After preparing the list of what all you are not, do not simply sit and whine like the 95 per cent of the population. Go think about overcoming your flaw through generating tremendous confidence.
In either case you are going to work upon yourself either by complaining or by creating value. Why not give a chance to upward momentum??
