"I know, I'm a _____"

"Trust me, I lost 40 pounds in a month. All you have to do is never eat, and run every day until you pass out in the street!"

Does anyone else think it's annoying when you try to answer someone's question with your best educated opinion, and someone comes along and tries to invalidate you with their self-proclamations of expertise? "Listen to me, I'm a bodybuilder", or "I know, because I own a gym", "Trust me, I'm a football coach," etc.
Don't get me wrong, it's good that you have a kind of expertise, and use a system that works for you, but there's no need to try to discredit the advice of others by dropping a title or name; I happen to train with possibly one of the most insane fitness coaches in the world, who makes Tony Horton's workouts look like a farm league baseball practice, and has taken me from fat to ridiculously good shape (or, conditioning) in half a year, but I don't think I've EVER name-dropped like that. The most I've ever said is, "this is what I learned from my mentor".
Now, not everyone has the same goals. My goals are sports-related, and require me to be pound-for-pound strong, not huge. If someone wanted to be a bodybuilder, I wouldn't recommend my workout regimen. If someone posts a thread asking "How can I get strong," the first thing I ask is what their goals are, then give some examples of what I mean. Unfortunately, when I'm trying to help with my humble advice, someone comes along and says, "Trust me, I do this for a living. You need to bench press 450,000 lbs 3 times a day for a week, and up your protein intake."
Okay, so that's an exaggeration, but if someone asked me how to be strong in the sense that I am, I would want to be able to help them without having to discredit everyone else around me. I shouldn't have to say, "Listen to me, I train with ______) to get someone to listen to me over a cocky bodybuilder (I'm not just picking on bodybuilders, I promise!). Bodybuilders, football players, tennis players, boxers, or people that just want to look good at the beach all have very goal-specific, different workout needs. I appreciate EVERYONE'S input when I ask a question, and think it's decent if others would respect my advice as being just as valuable as theirs.