Just being me

I've been working in my current job now almost 7 years. Every year I get in trouble with the management, not just my own manager but his manager too. I'm opinionated, if I have something to say I'm not afraid to say it, if something isn't going well I'll be the one to point it out, if people have a complaint about something or someone they come to me because I'm the one who will speak up, if I have a problem I'll let them know. Being this way has lost me "friends" but I've also gained respect. By being real I realise who else is real. Today, once again, I was called into the office for making a video blog on YouTube about our new uniform, I done it for the humour aspect, for the craic, taking the piss out of myself.
How can I stop getting in trouble....my own boss hates me because I speak the truth and he can't handle it.
It's kinda funny too though, knowing that my life is monitored (Facebook, YouTube, etc) to make sure I don't "step out of line".
One pathetic person even went to the trouble of printing out a full convo (83 comments long) that me and some others had on facebook once slagging off our work colleague, it was public, we had nothing to hide, but she printed it off and presented it to the manager.... I pointed out that this person knows I don't like them, knows I have no time for them, and I had the convo publicly so if they had a problem they could approach me....they didn't, it was some other slag who hated me tried to make a fuss out of it. My manager couldn't really bring it any further. Ha.

But this is who I am. I shouldn't have to change. But I'm getting really fed up with constantly being told off for having opinions. For being real.