Don't take anything. Solves all your worries
I second to this.
If you have so many worries and concerns, why take pictures in the first place?
There are many things, many objects, many themes, many sceneries, even if you think Singapore cannot make it, there are still many beautiful photos taken, just browse around this forum and you'll know how much you have missed it, even photos around HDB blocks also can turn out fantastic in photos.
Don't let your fear or shyness limits your creativity, photography is an art, and skill. No one is born to take excellent photos from day 1. It's progressive and learning process. Behind every award winning photo shot, there were hundreds if not thousands photos taken that were not shown.
If you are serious to go and explore into this hobby, then it's better move out from such fear, let your imagination run.
If you wish to take candid shot of people, then it's best that you can invest in a telecopic len, at least of 400mm. Then you can always take such candid shot from a much further distance away and the object may not even notice or aware that you have taken a shot on him/her.