hmmm... concerning the Hojou family...
1) the reason why Satoko cried: b/c she spill her lunchbox which is an offense that her Aunt or Uncle would literally beat her for.
2) Satoko is pretty broken mentally right now. Small things will trigger her outburst of crying.
3) Possibly Satoko forgot about this incident. Most likely all the things Shion did in this EP is NOTHING compared to what Satoko has to go through EVERYDAY at her house, physically or mentally. I mean think about it. A girl hitting her and throwing text books at her or Teppei using her as a punching bag outlet for frustration (+ we know everyone in Hinamizawa is an Olympian
) while her Aunt yells at her constantly all the way past midnight every night (See TIPs). Shion's
little outburst probably wasn't all that much compared to Satoko has been experiencing everyday for the past year, but yea, that chair was a bit too far...
Now see Satoshi's position in all this. He has to put up with this everyday shielding Satoko...
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Actually, I wonder what Mion said to everyone else to cover herself up. She did a pretty good job of it looking at everyone else's reaction after this.