Physical memories. Those can be the most powerful forces ever encountered.
Most memories that end up getting buried by the mind can only be excavated through very specific stimuli. A smell or sound can bring a few things back into the mind, and a visual cue can bring even more, but I think very few things can summon as many, as strongly, as a memory brought on by physical contact.
Think about a simple hug. If you stop and break down a hug (post-hug, not during, hopefully), think about what information you receive from that one gesture. You remember how tall the person is in relation to you, the width of their shoulders and their waist, the softness of their flesh, the firmness of their muscles, the texture of their skin, how you fit in their arms and visa versa.
Didn’t realize how much information is shared within that moment, huh? Now, think about how much of it you remember from your last meaningful hug.
See, even thinking about a hug brings back memories. Without the actual physical contact. Now think about how much came rushing back when you hugged that person. And even if you haven’t had a hug from that certain person in a while, one weird thing that the mind can do during a hug from a different person is remind you of the characteristics of that other person. Simple similarities make themselves known. Memories come back while, at the same time, new ones are made for the next time.
All this from some physical contact. So go and hug someone, ASAP!