I’d say about 33 of them.
Because I’d probably step on a bunch of them by accident, and I don’t think I’d be afraid of them really. But when the numbers start to go up…
:D:D
Or I forgot to suggestion something new!
Uh…
How about Doctors
Depends on the kind. Evil-looking, dead- or crazy-eyed ? One’s enough.
On the other hand, friendly, interested in your symptoms but tight lipped as to what you may have ? 3+ would make me worried, five or more and I’d go crazy.
How many coincidences ?
One is co-incidence, two is bad luck, and three is enemy action.
Chipmunks (non-CGI/non-singing type)
More than two would convince me I was being set up for…something.
How many squirrels?
100 red and 20 greys for a full-out blood-bath.
Have we had jugglers?
Two, if they’re juggling around me. Ten if they’re juggling on a stage in front of me.
Drill Instructors
I’m dental phobic, so one member of a dental school faculty is enough to totally freak me out. 
Sea anemones