"maybe its a matter of self confidence" Adversely, yes.
When one is flying the same routes day in, day out, it can become tedious. As we are all human we tend to "switch off" a little and can, if we are not very careful, become dangerously complacent.
On the other hand going to a lot of new airfields on a regular basis you tend to be more awake as you are ready and expecting more of the unexpected.
Been a victim of it myself and seen it happen on numerous occasions to.