Those are very funny. I just wave my hand at it and say, "oh, it's trivial. It's trivial."
I guess that counts as "proof by obviousness".
That's kind of my favourite. That, or the "proof by making everyone else feel stupid if they can't show something." This is usually done by using phrases such as "clearly," or "one can see by inspection that.."
I was reading a paper a few months ago when the author used the second method. I was stuck for ages thinking how this was clear from inspection of two equations. I brought it up with my supervisor who said "oh yea.. that's something that the author can do by inspection, but any of us mortals need to take two pages of algebra to show" :rofl: