Harry spoke out of turn.
Harry threatened his betters.
Harry brought up awkward subjects without regard to how uncomfortable they would make people.
Harry showed off how powerful he was when he really didn’t need to.
Harry totally cheated his enemies out of a well earned victory.
That all sounds Gryffindor.
The most Slytherin thing was done by McGonagal when she invoked a technicality.
Also:
Harry terrified that poor Dementor
McGonagall defied oppressors in defense of the powerless. That’s Gryffindor.
Harry spoke out of turn.
Harry threatened his betters.
Harry brought up awkward subjects without regard to how uncomfortable they would make people.
Harry showed off how powerful he was when he really didn’t need to.
Harry totally cheated his enemies out of a well earned victory.
That all sounds Gryffindor.
The most Slytherin thing was done by McGonagal when she invoked a technicality.
Also:
Harry terrified that poor Dementor
McGonagall defied oppressors in defense of the powerless. That’s Gryffindor.