Hand 1 - 3-bet flop. As played check-shove turn. Out of position you're shoving any river - and maniacs are more likely to fold to aggression on the river than any other street. Get it in on the turn and he's calling middle pair.

Hand 2 - See how differently life plays in position. You get to control the hand. I prefer raising the flop, as played turn check behind is fine as is river shove.

Hand 3 - Pre-flop good. Raise flop cos you're ahead here most of the time and hate overcards. Turn call as played, you have middle pair and showdown value so you want him checking the river - ten outs (if you're lucky) against a call doesn't make for a good shove. What's his calling range? Does the shove still make sense?