Time for me to jump in... Mateusz is not English and calls everyone strange things, he's not meaning anything derogatory by the terms Mr Dan or Mr Mike... However he is completely and utterly barking mad.
Having said that, he's his own person and is very welcome from my point of view to go and meet Mike, Dan, Akuzawa, Ushiro and of course Ikeda sensei or anyone else. I mention all of them on the classes but make no bones of the fact I felt more at home with Mike over Dan, doesn't mean Mateusz would think the same, I suspect he'd like Dan very much and I suspect Dan would like putting him on his backside just as much as we all do! Dan, should you ever meet a crazy Polish guy with angry eyes, it's Mateusz, although if he called you Mr Dan it might give the game away
Think of him as a curious puppy. He wants to see and know what the 'other' guys are playing at, tis all. Actually, we constantly get asked how long we've had our puppy when we take him out in public.