As a NOTE. Vash's canon is so hard to decipher that I won't be uploading links to what exactly his memories show. I will just summarize. You should thank me.
Memory 1 - Rem's final moments
What It Was - Alarms start going off, Vash and Knives meet Rem in the halls of the ship to ask wtf is going on. Rem tells them that something is wrong with the course of the ships and they are going to collide with a planet. She tells the boys they have to escape, and takes them to an escape pod. Instead of going in herself, she closes the door from outside, and tells Vash she will try to override the ships controls manually. Vash FLIPS OUT and says Rem has to come with them. As the door is closing, Rem says something to Vash, but he can't hear it over the noise. (It was "You must never leave Knives alone" or some variation of that).
What He Learned:-I love this Rem person, she raised us
-She is dead
-Lived on ships in space
-The ships were carrying many people (and they were all going to die?)
-Some basic technological information (what a computer is, what a spaceship is...)
What It Did:
Lol. Made him temporarily a little catatonic with grief. Vash's response to this memory is pure emotion. He doesn't know WHO Rem is, not really. He just knows that she died, she died trying to save other people, and he loves her very dearly and doesn't think he can go on without her. Being an empath, he can sync up with the feelings of his own memories very solidly, and since he doesn't know that it's Knives' fault the ships crashed, he doesn't have a distraction of anger. It's just SADNESS and it SUCKS.
Vash was really hoping for some sort of direction, on who he is, how he should handle the games, why he seems to feel things more acutely than others, and why he can't reconcile death and suffering the way others can. Instead he just got a kick in heart by finding out someone he loved more than anything is dead, apparently over an autopilot error.
His reaction was really compounded with the pillar. For Vash, time DID pass in the pillar. He was able to retain much of his rational thought in there, unlike Scarlet who just sort of shut down. So by the time he got back, it FELT like a fact that he'd learned months ago and could deal with. But it also still forced his general manner to be unhappy and negative. In light of Rem being dead, he was unwilling to leave Knives behind too. He still visits the pillar every day.
Memory 2 - Parading around town with a bunch of kids advocating Love and Peace
What It Was - This is a headcanon memory which takes place before July, but after Vash has separated from Knives. He has a regular group of friends among the local children, with ages ranging from about 3 to 12. They are all good kids, and today have decided to duckling after Vash, saying his trademark "LOVE AND PEACE!" and helping him help others when they discover someone needing help.
What He Learned:-Love and Peace!
-He's good at names (Jimmy, Tulip, Stanly, Sue, Bart, Brian and Choo, plus the names of about half the people they encountered)
-The weather is hot, the earth is dry and sandy, there are two suns
-The city was called December
-Knives wasn't in the memory, but he doesn't know where he was
-He has friends!
-Ice cream is delicious (pecan flavored!)
-Some basic identification stuff (There is a bar, this is a fruit stand, that's a sherrif...)
What It Did:It's a trivial happy memory, but happy memories are never
really trivial to Vash. He's very excited to get this memory. It is not exactly what he's looking for. What he mostly wants to know is how he's supposed to deal with conflict. But something happy to cheer him up is good too.
In this case, he's mostly excited about the fact that he has friends. He thinks of the memory as 'playing with friends', and won't notice how childish that sounds, nor has it occurred to him that it might be strange to have friends a fraction of his age. He also feels a little more like he understands that 'love and peace' were very important to him. Though at the time he wasn't thinking of the context of these words, and doesn't quite understand his own ideal. It's enough that it was a message he felt worth passing on to everyone in hearing, and he'll try to keep it in mind as he goes about Sabra.
At this point, Vash was being mostly reactive. He can't think of a way out of the games, so he defers to Allen (who Vash generally looks to for guidance, even when he doesn't like what he hears) and tries to put the pieces together afterward. Such is the case of the card game. He's upset that they were in fact playing Orion, but he also doesn't know what to do about that. Should they have refused to play the game? Would Orion have refused? Since no one was badly injured, is it important? He has FEELINGS on the subject, but no clear direction as to what should be done. So instead he handled it by trying to help repair the damage afterward. He doesn't feel like that is the correct answer so much as the only one available to him. But it made him feel a little bit better.
Memory 3 - Rem telling him about her favorite flower
What It Is - Rem showing Vash a geranium, her favorite flower. Vash is probably very young in this memory, only a few months old. His emotions are clearly rather underdeveloped, and also he'd never seen a flower before. The ships do contain GeoPLANTs, which are like parks in space. Though I think those only contain grass and a tree or two, it's possible they had flowers too, but he sure hasn't seen them yet.
Anyway, Vash asks her if you eat it =|a and she laughs, and tells him that flowers grow everywhere on Earth. She tells him she loves wild flowers, and the color red, which stands for love and passion, but also determination.
What He Learned:-Rem loev geraniums
-No flowers on spaceships
-Earth = Planet Rem has come from
-I've never been to Earth
-You may be able to eat flowers if necessary, but that is not the ideal
-Red is Rem's favorite color
-Red = Determination
What It Did:Thanks to this memory, Vash basically worked out a rough timeline. He knows that he's never been to Earth, but Rem and the ships come from there. He knows they were going somewhere, but did not get there because the ships crashed. And he knows in his second memory he was on a hot and barren planet, without any flowers. He's not sure where HE comes from, but suspects the ships were always his home.
He also remembers wearing a big red coat in his second memory, and now he's quite sure it was in memory of Rem. This makes him feel better. That he remembered her. Not that he thought he would forget her but... it's different to know you wear a symbol of something she loved every day.
He has also encountered the concept of 'determination', and will be pondering it over. There may not be any immediate, dramatic changes in his way of going about things. But he can connect the pieces... it was determination that let Rem sacrifice herself to save others. This was something Rem gave her life for, it's huge. It's Important. He should try to have determination, too. He's been getting too upset, too upset because he doesn't know what to do. Maybe he should decide what to do. It's not fair to wait for his memories to tell him. etc.