The biggest problem in today's modern Western society is we talk about our rights 99% of the time and about our responsibilities 1% of the time. Every single right comes with the responsibility. If I want to be a part of a harmonious society, then I need to make sure that I am a contributing part of it and that my actions or words don't make someone else's experience of that society any harder than it needs to be. I need to educate myself in how to communicate with people in a respectful way with freedom to express my own opinions but without forcing those opinions on others and presenting them as facts or universal truths.
You will never be able to please everyone, so why even bother? You do you. There are even those who will say if you never made any enemies, you're doing something wrong, the wrong being faking your way through life. You can be the nicest person in the world, and there would still be those who wouldn't like or agree with you.
In order to accept responsibility for your own thoughts/emotions/actions, you need to first be willing to stop the momentum of your thoughts and simply ask yourself: "Why am I thinking this?" Your thoughts should not be controlling you. It should be the other way around. You have the power to decide what you will concentrate on and think. Once you stop your certain train of thought, examine what has influenced you to think what you are thinking and try to determine the amount of knowledge you have about it. Gently move in the direction of self-realization and getting to know your own thought processes.
Staying positive, being happy, and not caring what other people think are all good things, but what if they are false? What if we don't feel them? Should we keep our smile on anyway? Nope. That is not only unhealthy and creepy but a definition of insanity. Your body knows when you are being dishonest with yourself. It feels how you are going against its natural flow, and it will come back at you with a vengeance in the form of various illnesses, mental and physical.
Looks are not important. They never were. Your health, on the other hand, is. If you want to lose weight to fit into society's standards of beauty, you are already doomed for failure.