When Hand Reading Goes Wrong?

[TazQ]

MP is a LAG. Forget preflop, curious as to what you think about my call down. (Yes, preflop isn't what I meant to do)

Party Poker 10/20 Hold'em (6 max, 6 handed) converter

Preflop: Hero is CO with 8[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/heart.gif[/img].
UTG calls, MP calls, Hero calls, Button folds, SB completes, BB checks.

Flop: (5 SB) A[img]/images/graemlins/spade.gif[/img], 4[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, BB checks, UTG checks, MP checks, Hero checks.

Turn: (2.50 BB) 6[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, BB checks, UTG checks, <font color="#CC3333">MP bets</font>, <font color="#CC3333">Hero raises</font>, SB folds, BB folds, UTG folds, <font color="#CC3333">MP 3-bets</font>, Hero calls.

River: (8.50 BB) K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP bets</font>, Hero calls.

Final Pot: 10.50 BB