Fjords seem to be the most adaptable horses around.  My  cousin had a few and one mare wouldn't do anything he wanted her to do while in a cart but when his 90% blind young daughter had the lines she was perfect never a drop of trouble anywhere on the road or in the ring. 

Nearly all horses respond very kindly to kids.. I have seen a horse that would pretty nearly kill any adult who walked in the paddock but would lay down with the youngsters.. 

Horses are as smart or smarter than a dog and are very intuitive.. I get called weekly to work on new horses that are known to be bad or anxious only to get there and they stand for trimming perfectly..  

Few months back I went to a new job and the guy walks into the stall of a stallion Mini and this thing tares after this guy on both back feet trying to punch this guy in the face with both front feet for about 5minutes.. 

Guy finally got the halter on and walked the horse out.. Looked at me and asked "Where do you want me to stand"..  Way, way over there I said.. 

The guy walked away.. I dropped the lead line on the ground and proceeded to trim all 4 ft with no questions, or problems what so ever..  just being ground tied.. 

The guy watching the whole time came over with a look on his face of total amazement.. When finished, he asked if I secretly drugged the horse when he wasn't watching..   I asked" Why would you drug this beautiful creature.. he was a perfect gentleman..  

He then informed me that both  stallions have been giving the 3 farriers before me a hard time and this one was the worst..  I've been back 3 times since the first visit and all of them have been perfect..   

People fail to see why horses respond the way they do.. In nearly 30 years of being a farrier I have only met 2 bad horses (genetically short circuited) but have met 100's of bad owners..