wait, who the hell is THEY?

So here is something I wonder... Why do people always want to give you advice by saying....'you know what THEY say.'........ Who the f*ck is 'THEY'? Who gets to be in this group who hands out information like, 'you shouldn't swim for 30 minutes after you eat...' I feel like saying...'listen 'THEY', don't tell me how to live my life.' Wait, how does one get to be a part of this 'THEY'? Do you have to try out? Is it a special club? Do I have to apply? Can I get a student loan for this? Or maybe I too can just start my own fascist regime of sorts where I can just start handing out random information under the guise of 'THEY'. Yeah - that's it!!! Like, 'you know what 'THEY' say, you should give me a dollar every time I give you advice' or 'you know what 'THEY' say, honking too much can mess up your car' 'you know what 'THEY' say, picking your nose can give you nose herpes'...really, anything - no matter how random, could be used.