That thing that makes you say UGH! If only I had/could do.
TIME
30 years would be the minimum I would consider. 100 more years would be delightful.
A teleporter would be fifty shades of awesome. A two hour jaunt in milliseconds? Take my money and get me where I want to go.
The time I wasted on the myself and others. I love who I am now. I just wish I had the opportunities I once had with this frame of mind. As the old saying goes "youth is wasted on the young" lol! But if it had to be something tangible, I'd buy a Harvard education or I'd pay for a Harvard education in Bio-Chemistry