If I could travel back in time to any decade, it would be the 1900's. 
I would go to a hair dresser right away and get the Vintage Updo Hairstyle. So I am going to wait for time travel to become possible - and go to the hair dresser to give me the perfect look of a Vintage Updo Hairstyle.

The second thing I would do once I arrived back in the 1900's would be to go shopping and buy a lifetimes supply of outfits. It would be super amazing to go back in time and stock up on one's most desired fashions.
I literally daydream about doing just that sometimes.

I would really love to go back to that era. The music, fashion, theatre... everything looks so wonderful.