There's really three questions here;
(1) Whether you believe yourself to be more intelligent than others
(2) Whether you measure or test others to see their intelligent relative to yours
(3) Whether you boast or mock others based on your perception of their intelligence
The first question is subjective; and is almost entirely influenced by one's peer group. It is very possible for a "stupid" person to feel very intelligent simply because they are surrounded by other unintelligent individuals.
Likewise it is possible for a person of above-average intelligence, perhaps even in the 90th percentile or higher, to feel very stupid. If they're consistently surrounded by other intelligent people, they may feel very unintelligent.
Because of this, I think that our own perception of intelligence is demonstrably incorrect. I can count hundreds of very "stupid" people who believe that they possess above-average intelligence. They're wrong.
And yet I consider myself to have an above-average intelligence. I know that if I were surrounded daily by intelligent individuals with PHDs in my field, I'd likely feel differently.
So (1) as a question is inherently unknowable.
I think that (2) is a given, as people consciously and unconsciously measure themselves against every person they meet. It's human (and even animal) nature to do so, and I don't think there's anything wrong with saying YES, I believe I am more intelligent than this person.
(3) is very unfortunate, and choosing to mock others often ends up hurting the mocker as much as the recipient. It is rare to find a person who enjoys being told they're stupid, and I see no need to share my perception of other's idiocy. After all, it's only MY perception.
On top of that, persons claiming extremely high intellect often look silly when they stand up and declare their intellect as superior, because they've likely made an error themselves.
Like incorrectly spelling separate. 
