1) Just sat down and have been playing for a few minutes.

PokerStars No-Limit Hold'em, $4 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

SB ($215.70)
BB ($400)
UTG ($406.20)
Hero ($533)
CO ($374.60)
Button ($624.55)

Preflop: Hero is MP with 9, 9.
UTG raises to $16, Hero calls $16, 4 folds.

Flop: ($38) 3, 6, 8 (2 players)
UTG bets $28, Hero calls $28.

Turn: ($94) 9 (2 players)
UTG bets $75, Hero calls $75...

2) A while later on another table.

PokerStars No-Limit Hold'em, $4 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

BB ($571)
UTG ($394)
MP ($473)
CO ($879.20)
Button ($487.80)
Hero ($501.10)

Preflop: Hero is SB with 3, 5.
4 folds, Hero raises to $16, BB calls $12.

Flop: ($32) A, 5, A (2 players)
Hero bets $25, BB calls $25.

Turn: ($82) 8 (2 players)
Hero checks, BB bets $55, Hero calls $55.

River: ($192) K (2 players)
Hero bets $121

3) A little while later on another table. I chose to call preflop because given the dynamics of the game at that time, I thought 3-betting would allow him to play the hand more perfectly and I could control the pot having position.

PokerStars No-Limit Hold'em, $4 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

Hero ($549.80)
SB ($330.90)
BB ($89)
UTG ($398)
MP ($416.65)
CO ($495.50)

Preflop: Hero is Button with J, J.
UTG raises to $16, 2 folds, Hero calls $16, 2 folds.

Flop: ($38) 3, 5, 8 (2 players)
UTG bets $28, Hero calls $28.

Turn: ($94) 2 (2 players)
UTG bets $76, Hero calls $76.

River: ($246) K (2 players)
UTG bets $278 (All-In), Hero ???