I'll be only talking about this part since that block of text is giving me a headache. No fault on your own, I just can't handle it unless it's chopped up nicely. XD!
" 1- Is the person suffering from depression, stress?
2- Will this affect my future? or is it important?
3- Will me being positive, drive the other person to be positive too?
4- Does it waste my time?
5- Should I take it to seriously? "
1.) As a long-term sufferer from depression whom did not know the signs of my own disease (IE, being /incredibly/ lazy, not wanting to do anything, frustrated with myself and my lack of strength in the emotion department) You should always remember that no-one person is the same. Some people don't like their body, while I am a perfectionist and want to do my best at what I do, not what my body looks like. Some people could pretend to be goofy and fun, and others would just put it right in your face. Some could be perfectionists and some could put up a front like bullying others or making themselves seem to high and mighty to hide the fact. (Darn it I made my own block of text. Shoot.)
2.) You never know if you are going to have an effect by helping the said person. I've heard of a story when a pediatrician pushed himself to the absolute limit to save a child from certain death that looked nearly impossible. Cue in a good few decades in, and that said child saved the pediatrician from certain death when everyone ignored him. So, push yourself to do the best you can with what you have. <3
3.) Honestly, don't force yourself to be a grumpy emo person just so that person feels like they don't have to be positive. Neither should you force on a happy face just because of the pressure. Be yourself, whether that includes being a hairy chubby mammoth of a female, or a skinny little twig of a male. Maybe the hairy chubby mammoth has an incredible amount of self confidence and can help the skinny little twig of a male be himself and grow stronger just by the mammoth being their self. (Making fun of myself and my boyfriend, lol!)
4.) Anything that you can scoot into your schedule that is a good deed that may or may not be seen by the world should be done. Maybe you'll run a bit late with your boss, but you could save someones' life by pushing them away from suicide just by giving a bullied teenager a hug and telling them only their opinion and theirs alone matters to them, that they should ignore the bullies.
5.) Take it the way you would take it, flaws and all. Showing yourself as yourself is much better than pretending to be the best optimist in the world. I, myself am sometimes looked down upon by my blunt (I curse in private w/ friends.) and slightly rude I've been told? Personality? Eh.
That's my thoughts.