In contrast to some other parts of the world, Canada is not a nation with a lot of obscene or offensive gestures. In general, most rude hand or body gestures are done knowingly, and can be easily avoided as a result.
Some of the most common “bad” gestures include:
Raising only the middle finger — an extremely obscene gesture of anger/frustration towards someone else.
Thumbs down — mild gesture signaling disapproval.
Elbows perched on the table while eating — generally considered rude in formal settings, though common in more casual situations.
Eating with an open mouth or talking with a full mouth; unapologetic public belching, nose-blowing or other releases of bodily functions — all considered extremely disgusting and are usually expected to be followed by an apologetic “Excuse me.”
Sneezing is weirdly ritualized. Sneezers say “excuse me” following a sneeze, while anyone in the immediate vicinity says “bless you,” as a sign of sympathy.
Pointing or staring at strangers — considered rude and a form of leering.
Conversely, not making eye contact with the person one is speaking to is considered a rude form of shyness or bored distraction.
Though attitudes can be more forgiving in hot summer months, most indoor businesses generally hold firm to the “no shirt, no shoes, no service” principle. Public nudity of any sort is illegal, and attempted only by the most avant-garde and attention-seeking.
There is something of an ongoing debate in Canadian society regarding “public displays of affection” or “PDAs,” such as cuddling or passionately kissing in public places. Some may find such displays easy to ignore, while others consider them quite gross and offensive. Unfairly or not, homosexual partners continue to be judged more harshly in this regard.