I am amazed at plumbing. Getting access to water for our various tasks is amazing to me. We don't have to go to the creek or draw water from a well to cook or take baths. Toilets and hot showers, in particular, are a truly a comfort!
I'm also amazed at how quickly we can communicate with people around the world. Email, cell phones, internet forums, chat rooms, online video games, etc. Even 20 years ago we couldn't communicate this easily! I can talk to someone in Japan or the UK and it's as if there is no distance at all. Truly amazing.
What also amazes me is the rate at which technology is progressing. I look and think about the technological difference between the 1700's and 1800's (not much for the most part) and then the difference between the 1800's and the 1900's and it's staggaring! Now in the 21st century, it's even going to be more amazing.
It's so exciting to me to be living in this day and age. Even more exciting is the thought of living in another life sometime in the distant future! What will life be like? What will I see and experience then that I can't possibly comprehend now? It boggles my mind.