As a species I think its different according to country,some places it feels good to be alive,you bounce out of bed every morning.As individuals it's far more complex,some have a glass half full,others half empty,I had a non-verbal autistic young bloke approach me in a store a few weeks back,he zipped my jacket right up,his carer said to me "Don't be alarmed",i wasn't,we are all wired up different,I gave him a fist-bump and a thumbs-up when they walked off,he smiled.