I had to think about this one JB because to observe suspicious behaviour you may need to stare: for example, if a person in a book store behaves strangely, the owner would need to observe him very closely (stare) to ensure nothing is stolen. But I remember my mother always impressed upon me that it is impolite to stare at someone.
Ok, how about, if you are observing a person, it is not necessary to follow him/her around or come up very close to the individual, making him or her feel uncomfortable because you are invading their "space."
Edited: Geenie on 9th Oct, 2009 - 1:29am
I put this tip based on general observation. If you are observing criminal-like behavior you would still need to observe with discretion, after all the idea would not be to alert the person to your observing them. The kind of observation I am talking about is where someone enters a room, you look at them to note their entrance and then look away, but the Trini version is to stare, maybe even have the mouth slightly open and then follow the person's every movement. Now if I were caught observing someone (because they looked at me) then I would quickly look away or give a friendly grin / smile, but not Trinis - they continue to stare as though they are glassed eyed.