Why aren't people as honest as they should be?

Throughout my adulthood and youth I've noticed a pattern---I do something stupid or something that requires intervention and no one tells me until I hit rock bottom and discover it myself.

In high school teachers told us trades and retail could make us 70gs a year and get us the house in the suburbs what they or our parents didn't say is they're fragile and depend on the economy and once the economy hinders the first things to go are trades and retail.

I was 100 lbs over weight, no one told me until my stepmom took a pic of me that looked like I had a beachball under my top. Again not a word in fact she still begs me to gain it back saying no one wants a skinny guy.

I decided to go off my Dexedrine when I was 14 no one said its a bad idea now I have shitty grades and am deathly afraid to mail my transcripts to anyone.

Then to top it off yesterday I found out in a loud, over talkative, obnoxious, robot icky efficient prick at work only after my company offered me an ultimatum.

My mom and I are strong independent Ukrainians she told me all these except the last one but when one person says it you never believe it. I say it to people too. Why can't more people?