My mum is pretty free with her praise, but her mother, my grandma, seemed to think it would spoil us, or something. I was the oldest of her grandchildren, and so the first to do all the milestones. When I got good grades for my o'levels, she said 'I'm sure [cousin x] will do better.' When I passed my driving test, and offered her a lift home, she said 'I think I'll wait until one of the others learns to drive'. Etc etc. Didn't affect me overmuch, but it must have been torture for my mum.
Apparently she did exactly the same to our cousins, maybe thinking the competition would spur us on.
The last time I saw her before she died, she held my hand and said 'You know, I did always love you, you know.'
Well why didn't you show it, you poor sad old thing?