1st sick: My job - Oftenly have to face rude people.
2nd sick: My colleague - This colleague of mine told my boss i'm late for work. And didnt even inform me when she is not going to turn up for work.We share the same duty,therefore must always infrom each other if 1 can't turn out for work.So the other can find a subsitute.
3rd sick:My supervisor always blame other people faults on me.
Case 1

: No matter if it's the customer at fault or vis versa, customers are always right according to the rule.
Haven't you think in the customer's point of view? What if you're the customer and you have waited at the long queue feeling too hungry? (This is just an example why customers might be mean. In general cases, most sg people tend to be more stress than other people in developing countries.) Hence, experiencing the stress and the hungry their face might show they're not satisfied with your service, but in fact they're unsatisfied with themselves.
Give them a positive attitude by smiling and saying sorry if you see they're not happy with your service. In return, the customer will feel contented by your service even though they might be very angry.
Case 2 & 3

: I don't think there's a need to care about the silly actions of the colleague of yours. What matters most is your belief in yourself that you did everything from your own conscious. You don't need to show anyone that your doings are right and that they are in the wrong- because they're nobody to u! Just act as normal, their actions are not a threat to you; be your positive self. Don't ruin your own image by just dealing with one or two people who doesn't like your trueself. Report to your supervisor about your colleague's irresponsible actions before you actually get blamed for them. Example: Boss, you saw who has been absent today, and she didn't even care to inform me the last minute; I didn't have enough time to clean up her mess.

Ok, I dunno what's with this threat but I believe noone has any right to stop anyone from replying to this threat other than the moderators. If you can't accept anyone's idea, you can just disagree with them and not cast any individual's vengence. Of cos, people can say it's either the customers or your supervisor is at fault but in fact everyone needs to go through constant changes to grow. Who is the person who is in need of help now? It's you yourself. It's a good sign that you are able to learn by getting comments about yourself rather than getting bad complains about other people around you. You already know people might treat you in a way you feel uneasy, people don't need to translate the facts and tell you again.