There's a time and a place for self-deprecation, and responding to "Why should I hire you?" is pretty much never it. I'd recommend thinking of some decent answers to that one and having them to mind because you'll probably encounter that one alot.
I grow up as a loser
So? Our past is just that, the past. It needn't define your present or future unless you choose to let it.
no success at any sports
So? Unless your job interview is for a role playing sports it doesn't matter one jot.
not good with girls
So? Unless your job interview is for gigolo or the starring role on The Batchelor it doesn't matter.
overweight with a BMI of 28
So? Some of the best developers I've ever worked with would smash that into the weeds. You code with your brain not your belly. And what does it matter anyway - so you're overweight. If you don't like it - change it. I'm not saying it's easy, but let's not pretend that it isn't possible.
dropped out of college
So? We've all failed at things in our lives, it's what you do afterwards that makes the difference about whether you're an Arnold or Ace Rimmer. If your field means you need a college degree then go back and try again. If at first you don't succeed and all that. If not then prove you can do it in other ways, through work experience or personal projects.
my questions keep getting negative scores in this website
Your cumulative score is still +14 at time of writing. At the risk of getting a bit meta for the main site here; I think it's relevant to this question to point out that the one's where you're basically moaning get negative scores. Whereas the one where you showed a positive attitude and wanted to do better got substantially upvoted and favorited 4 times (at time of writing).
I think there might be a useful lesson in that which you can apply to your job hunt approach.
have you ever hired a loser guy or not
if so why did you hire?
Well once was because I could see that they were actually better than they thought they were - took me a couple of years to turn them around but they were one of the best employees I've ever had. The other.. well, he was a friend. That's my only excuse really - still the worst hiring mistake I've ever made.
But that's irrelevant - because you aren't a loser. You've just got yourself in that weird place that humans do sometimes where it's easier to self-sabotage. I get it, sometimes it's just easier to whinge and moan rather than actually doing something to make your life better - even if that moaning is aimed at yourself. Heck, I've been there a few times myself. But it doesn't help anything. It doesn't change anything. Instead look for things you can do that will make yourself and your life better - because really you are worth it. Everyone is.
So if you get asked "Why should I hire you?" Instead of answering "Only if like losers" you should answer "Only if you want someone who is always striving to do better then they have before"