I get paranoid with them, no matter how many of the headcrabs you kill, there's ALWAYS another one waiting to jump out at you.
Like that house in HL2 that has one
I was playing synergy and went into that house
And I went in there and heard hissing and froze in place.
I looked around and procceded with a crossbow
And I jumped into a door and SAW THEY BLACK MENACE THAT IS a POISON ZOMBIE
SURROUNDED BY POISON HEADCRABS
I also got scared by the other 2 story house in the coastal levels in which you have to use props to get to the 2nd floor
Just mindin my own business
then BAM
3 ELECTRO-BALL THINGIES COME OUT OF NOWHERE AND ATTACK ME
and I shoot em out da window