Paddling: could that be a mental art as well?

Last wednesday-evening I was paddling a Baidarka with a kinetik wing-paddle for a tour from home to the kayakclub and back; in total approx. 20km.
For this occasion I took my GPS with me for recording speed. At first I adopted as a target to paddle at 8-8,5km/h, because it felt quit relaxed this evening and as an experiment how I could maintain this.

At a certain moment my GSM came to life: ring-ring: Jos here!; Where are you?
Jos was paddling in the northern part of the "Alkmaarder meer" and we made an appointment to meet somewhere in the middle. From that moment on I let go my speed-target and decided to go for the highest speed possible for the distance. At first this was something between 9-9,5km/h. After a while however, when coming in some kind of a cadence, I noticed I went down to 8-8,5km/h, although it felt as if I was working harder than before. Strange!
As I heard my paddel blades bubbling cq. cavitating while pulling through, I tried to concentrate on tecqnique and forget about speed. This worked: as the cavitation noise disappeard, my strokes were longer again and with the correct body-rotation, I reached the 9,5km/h easily again.

5 minutes later: I spotted 2 clubmembers ahead of me and automaticaly I started thinking of overtake them.
And again the speed dropped an again I succeeded, after realizing this, to concentrate again and to speed up.

Later in the evening I was paddling home again. As it was later than planned, I was very eager to arrive at home and tried to go for the highest speed I could reach.
But again I was was only cruising at 8-8,5km/h. This time however I could not forget my desire to go fast AND thus my speed did not become higher.
Partialy this could be due to getting tired, but as paddling felt different now, not as fluently as before, I concluded that the maximum speed you can reach, is partially also a mental issue.

When you are too eager to go fast, you can't.

May be the message should be: relax your mind and just go!
So there is still something to learn