The thing is, albeit being extremely abstract and not directly measurable, we keep finfing new evidence that Einstein was correct. Actually, we are systematically finding them at a faster pace, perhaps because we gain insight as to what to look at next based on previous results or because more
and more people are intrigued by the subject and spend their lives searching for proof.

One thing is certain though, our lives would be very different without the principles of General and Special Relativity =)

http://www.youtube.com/watch?v=NtnsHtYYKf0

http://www.youtube.com/watch?v=C2VMO7pcWhg