Why Do We Base So Much on Opinion Polls?

I'm not just talking about pre-election polls, I mean any sort of poll or survey. They fully rely on the person giving the answers to be honest. But how can anyone be sure?

My 13 year old son, a Grade 8 student, was just telling me about a survey they all had to do yesterday that had questions that sound like it was mainly a 'mental and physical health' questionaire. He doesn't know a single solitary kid who filled their's out honestly, aside from himself. There were questions like 'Do you smoke?' and many of his friends checked off the answer showing the most amount of cigarettes smoked each day. There were mental health questions surrounding sleep - some of which were answered that the kids do not sleep very well and cry every night. Things like that.

So what is the school to glean from these surveys exactly? The kids were apparently all laughing and joking about them later, giggling together about the stupid answers they gave. Does the school look for ones where every possible silly answer was given, and then toss them out? How then do they get a good idea of what students in the school are doing, how they are feeling, etc if half the surveys have to be tossed aside. The whole thing seems pointless.

It also made me think of when Alberta Health and Wellness was calling around last year asking people if they wished to take part in a survey. I refused to do it when they called me, but my 23 yr old coworker agreed. Some of the questions made her very uncomfortable, and it made me think about how many people really answer those surveys honestly as well. It's not exactly an anonymous survey if they called you at home lol. They know your name, phone number, address, health care number, at the very least. Would you want to answer truthfully about suicidal thoughts, your lifestyle, etc when the surveyor knows all this information about you?? But the content of some of the questions also surprised me. She was asked things like 'When you go to bed at night, do you go to bed alone?". This came after being asked who she lives with already (brother). She started to get really annoyed with the questions and could not believe it was a govt agency doing the asking. How many others felt the same way and gave sarcastic untrue answers in 'protest' of the questioning? How can anyone rely on the results of such a survey? Why do we even bother?