First hand is an instant fold. You shouldn't be considering calling/pushing with someone betting into you and this many people in the hand.

Villian's action in the second hand is how a lot of bad people play low/middle pairs. They check the flop to the raiser to induce a bluff or a Cbet, but they aren't folding because there are all low cards on the flop. I think you should've just called his raise preflop and played poker on the flop. Because you did reraise so huge, and the pot is so big, I suppose a push here isn't that bad. You'll spike and ace or king about 25% of the time anyway when he calls your "obvious bluff" with his 6s.