My biggest leak lately seems to be stupid cards. Is there any way I can avoid situations like this? Here's my most recent example hand:

Texas Hold'em $1-$1 NL (real money), hand #1,193,935,091
Table Tbilisi, 22 Aug 2005 03:01 PM

Seat 1: c bax ($19.75 in chips)
Seat 2: 69_camaro ($28 in chips)
Seat 3: marklar85 ($27.50 in chips)
Seat 4: lemo8 ($111 in chips)
Seat 5: Raider83X ($36.50 in chips)
Seat 6: JonboyAU ($59.50 in chips)
Seat 7: Galapogos [AD,AH] ($99 in chips)
Seat 8: LFCMarc ($107.25 in chips)
Seat 9: LugNut25 ($96.50 in chips)
Seat 10: steelerfanz ($71.50 in chips)

ANTES/BLINDS
Raider83X posts blind ($0.50), JonboyAU posts blind ($1).

PRE-FLOP
Galapogos calls $1, LFCMarc calls $1, LugNut25 folds, steelerfanz folds, c bax folds, 69_camaro folds, marklar85 folds, lemo8 folds, Raider83X calls $0.50, JonboyAU checks.

Yes I'm aware I commited the sin of slowplaying AA here but I was expecting raises following here. Anyway, on with the rest of the hand

FLOP [board cards 4D,2C,7D ]
Raider83X bets $1, JonboyAU calls $1, Galapogos bets $3, LFCMarc folds, Raider83X calls $2, JonboyAU calls $2.

Should I have hit the flop harder? Aside from a flush draw I felt pretty safe at this point

TURN [board cards 4D,2C,7D,JD ]
Raider83X checks, JonboyAU checks, Galapogos bets $5, Raider83X folds, JonboyAU calls $5.

Throw out a bet to test for flushes...

RIVER [board cards 4D,2C,7D,JD,QS ]
JonboyAU checks, Galapogos bets $10, JonboyAU calls $10.

Really sure this guy didn't have a flush so I bet out another 10 to rep it myself (I was holding the A after all) and push him off whatever he was on

SHOWDOWN
Galapogos shows [ AD,AH ]
JonboyAU shows [ 7C,JH ]
JonboyAU wins $41.


Ok so is this an unlucky hand? Or is he stupid for not fearing a flush or set. Or am I stupid for not playing this harder on all streets but the river? This stuff is happening to me a lot and I want to know what to adjust to stop it. Please someone rip apart my play here.