Some poor river plays

Just got done playing the good 'ole $2/$4 6-Max and I wanted to give you a couple of hands that actually made me laugh.

$2/$4 Texas Hold'em
Seat 1 is the button
Total number of players : 6
Seat 1: the_proute ( $147 )
Seat 3: gastfrench ( $193.06 )
Seat 2: Hero ( $155.38 )
Seat 4: magic1948 ( $170 )
Seat 6: JuuuuustCall ( $185 )
Seat 5: peekonrush ( $100 )
Hero posts small blind [$1].
gastfrench posts big blind [$2].
** Dealing down cards **
Dealt to Hero [ 3s As ]
magic1948 calls [$2].
JuuuuustCall folds.
the_proute calls [$2].
Hero calls [$1].
gastfrench checks.
** Dealing Flop ** [ 2h, 4d, Ac ]
Hero bets [$2].
gastfrench calls [$2].
magic1948 folds.
the_proute folds.
** Dealing Turn ** [ 5s ]
Hero bets [$4].
gastfrench calls [$4].
** Dealing River ** [ 9h ]
Hero bets [$4].
gastfrench raises [$8].
Hero calls [$4].
gastfrench shows [ 2d, 2c ] three of a kind, twos.
Hero shows [ 3s, As ] a straight, ace to five.
Hero wins $34.50 from the main pot with a straight, ace to five.

Excellent slow play -- wait until there's a 4-straight out there to put in the raises with your set. Do I need to start 3-betting the river in these spots? I always think that I'm tying at best, so I don't want to end up feeding the rake or putting 4 bets in with the idiot straight. I really don't know whether I'm ahead here often enough to 3-bet... gonna have to think about that one.


$2/$4 Texas Hold'em
Seat 5 is the button
Total number of players : 6
Seat 1: StacysMom340 ( $128 )
Seat 5: LittleTara1 ( $126.50 )
Seat 6: Genew222 ( $66.75 )
Seat 3: Hero ( $167.25 )
Seat 4: Poker54261 ( $209.16 )
Seat 2: ROFLOBSTERZ ( $114 )
Genew222 posts small blind [$1].
StacysMom340 posts big blind [$2].
** Dealing down cards **
Dealt to Hero [ 9d Ad ]
ROFLOBSTERZ raises [$4].
Hero folds.
Poker54261 raises [$6].
LittleTara1 raises [$8].
Genew222 calls [$7].
StacysMom340 folds.
ROFLOBSTERZ calls [$4].
Poker54261 calls [$2].
** Dealing Flop ** [ 4d, Jd, 3c ]
Genew222 checks.
ROFLOBSTERZ bets [$2].
Poker54261 calls [$2].
LittleTara1 raises [$4].
Genew222 calls [$4].
ROFLOBSTERZ raises [$4].
Poker54261 folds.
LittleTara1 calls [$2].
Genew222 calls [$2].
** Dealing Turn ** [ Js ]
Genew222 checks.
ROFLOBSTERZ checks.
LittleTara1 bets [$4].
Genew222 calls [$4].
ROFLOBSTERZ calls [$4].
** Dealing River ** [ 7c ]
Genew222 checks.
ROFLOBSTERZ checks.
LittleTara1 bets [$4].
Genew222 calls [$4].
ROFLOBSTERZ calls [$4].
LittleTara1 shows [ 5s, 5h ] two pairs, jacks and fives.
Genew222 shows [ Ks, Kh ] two pairs, kings and jacks.
ROFLOBSTERZ shows [ Kc, Kd ] two pairs, kings and jacks.
ROFLOBSTERZ wins $37.50 from the main pot with two pairs, kings and jacks.
Genew222 wins $37.50 from the main pot with two pairs, kings and jacks.

Note that instead of just calling 3 bets cold preflop he just goes ahead and caps with 55. Awesome. I think his river bet sucks too.

Maybe I just have no idea how to play on the river and my opponents are geniuses, cause I just don't get it.