I know it is a petty issue and I am being so too. But I have to confess it pisses me a bit when someone tries to discredit my help, thanks to which they can get the work done, after which, however, they need to believe they have done it all by themselves in order to boost their long oppressed egos. I understand that. I understand someone who always fails something beyond their comprehension needs that from time to time, but it doesn't mean I don't mind being used unrecognized. I am happy to see that my effort has fruit and they progress but I don't appreciate their self-illusion. But again, like I said, I am fully aware of the pettiness of the whole thing. I guess guinea pigs cannot understand the theory which is being tested in the experiment performed on themselves.