I got this theory a while ago regarding mirrors. When you look into a mirror, you in fact see what's in the next universe over in the long line of infinite universes. In that universe, everything looks the same, and in fact it is, except some small part of your universe is different. It could be as small as a 13-year-old in Cuba deciding to brush their hair one more stroke than in your universe, but it's different nonetheless. If you take two mirrors and make them face each other so you get that infinite reflection thing, you can see into the universes on either side of your place in the line, and if you had perfect, telescopic vision, you could eventually see into a universe where there is something different shown in the mirror, like you wearing a different shirt or having different color eyes. This is what I come up with when bored.