I would imagine most posters on this board are, de facto, "thinkers" to some degree ~ that's why you are here. However I'm not sure if you will relate to the following or not, which is on a lighter note than some of the above posts.
Non-thinkers may or may not be deep-down happier ~ but they do sometimes seem to have more fun, at least the non-religious ones. They skate across the surface of life without looking into the depths, untroubled by philosophy, ethics, Truth or the nature of reality.
I remember very clearly the moment I discovered that it is not always helpful in all circumstances to be a deep thinker. One afternoon when I was a teenager, I watched a TV wildlife programme showing how birds and animals attract a mate by displaying, preening, calling, dancing, strutting, fighting and drawing attention to themselves, males trying to assert dominance and display strength and prowess and females being choosy and coy but also hoping to get noticed by the males.
That evening I went to a noisy teenage party and when it was in full swing, I found myself analysing the reasons why I and all these other people had chosen to spending our time jumping around, flirting, posturing, hips gyrating to the music wearing fashionable clothes, jewellery, perfume and make-up (it was the '70s ~ some boys wore make up too!), and the scene became high comedy to me when I compared it to the wild-life film and saw the parallels between the two. I suddenly couldn't dance any more. I felt terribly self-conscious and ridiculous and it killed the spontanaity. (BTW I have never taken drugs and was not drunk.)
I thought about how the people in the room believed they were so cool and sophisticated, but in fact they were behaving no differently to animals. I was watching them watching each other, aware of the unspoken sub-text going on behind everything that was happening. I was analyzing the reason why the girls were fiddling with their hair and the boys were standing legs wide apart playing imaginary electric guitars. It seemed all the weirder because my friends were not conscious of or thinking about the motives for their behaiour, they were just following their instincts.
My thinking spoiled my evening, From then on I could not get rid of my self-aware thoughts and do what my friends were doing. I desperately wished I could be like the others and NOT THINK, but just mindlessly enjoy myself. I did not say anything as I felt sure no-one would have a clue what on earth I was on about if I tried to explain, even though my friends were all intelligent. They were just not in thinking mode, not analyzing, but just happily existing in the moment.
It's an example of how I have found conscious thinking can occasionally be a bit of a disadvantage in some aspects of every day life. However when life is hit by problems, it is usually the thinkers who have the advantage.
I'm not sure if anyone reading this will understand what I felt at the time or whether it was just me that was odd and in my own little world!
Footnote: I am pleased to say I have over the years more or less learnt not to be a thinker all the time, so I can now enjoy dancing without caring if I am behaving like a baboon.