Saika actually ‘Traps’ people into believing that he is a girl.
This mistake has often occurred in the series, to the extent that I couldn’t ignore it. He tries to act as manly as possible but his soft nature and female-like appearance actually confuse Hachiman, the main character of ‘Oregairu’, who often thinks of Saika as a girl.
Now, this character is on this list because of that meaning of Trap which I explained in the intro.