I really think that depression is merely just the result of certain chemical reactions in the human body that make people think and feel a certain way and seriously, people are taking these emotions seriously as everybody has each of their own 'set of rules' and is able distinguish between their definition of 'right and wrong' and be able to sort out their 'feelings'. Like for example when you beloved boyfriend/girlfriend ditches you, naturally you would feel bad and stuff, but really, its stupid to do 'stupid' stuff over such an issue, all that person needs to do is to sort it out himself/herself and just reflect and get over it already. Such resources be put to use more meaningfully on other things and not on such things, if those people really cannot sort it out themselves, and make such a huge fuss, I believe they better off dead and not jeopardize the whole world's progress. If you think this is horrible and not really 'good', this is just the way of life and just get over it. People in third world countries are living much off worse, and are facing real world problems instead of all these 'emotional struggles' people impose onto themselves so really, why bother as all these are just part and parcel of life and are all common in the passage known as life, so all these people should just face it upfront and forget about it already. And about the thing about handling all these stuff, like mentioned above, knowing that many things would lead to feeling depress I would take time to reflect on whatever that has happened and ponder upon myself and ask myself what can be done to alter the situation and find out why am I even feeling depressed in the first. About loneliness, its just a feeling of isolation people experience when they are lonely/ left behind, to solve this problem, the victim should learn to mingle around a little bit more to get to know more friends, as friends are very crucial and add a lot of 'spice' to your life, and definitely you wouldn't be lonely anymore. The same also applies to being different from your friends, get to know them better, and you might find friends with common interests but in the first place we shouldn't even discriminate people in the first place and have them left out on certain stuff/occasions. And finally about putting up front, its the 'ideal' image you want to project to others, in order to hide your weak inner self and not let people invade that 'space' and to not let people see your weaknesses and flaws and that they would think otherwise but however I think that this is totally useless as it is very difficult and tiring to put up such a front and sooner or later people are going to find out that you are just 'faking' it and I really think might as well people just let it all out at once instead of just bottling it up and accumulating this burden on them and just resolve the matter and be just yourself.