Why do i continue to do this?

[Pasterbator]

I can't explain it. In this instance it likely cost me between 200-300 chips. Can someone just tell me i NEED to bet this turn??

***** Hand History for Game 2223638784 *****
NL Hold'em Trny:13188353 Level:2 Blinds (10/20) - Saturday, June 18, 00:03:21 EDT 2005
Table Multi-Table(368746) Table #5 (Real Money)
Seat 7 is the button
Total number of players : 10
Seat 1: Pasterbator ( $2450 )
Seat 2: bjuliano ( $765 )
Seat 5: floyd_1977 ( $2600 )
Seat 8: thebbbman ( $3110 )
Seat 6: rickmp ( $650 )
Seat 7: trainwreck10 ( $1680 )
Seat 3: lopneeb ( $1245 )
Seat 9: BklynnsDad ( $1295 )
Seat 4: ckknight ( $2040 )
Seat 10: NLVPOKER ( $895 )
Trny:13188353 Level:2
Blinds (10/20)
** Dealing down cards **
Dealt to Pasterbator [ Jd Js ]
NLVPOKER folds.
Pasterbator raises [75].
bjuliano calls [75].
lopneeb folds.
ckknight calls [75].
floyd_1977 folds.
rickmp folds.
trainwreck10 folds.
thebbbman folds.
BklynnsDad calls [55].
** Dealing Flop ** [ Jc, 4c, 9d ]
BklynnsDad checks.
Pasterbator bets [150].
bjuliano calls [150].
ckknight folds.
BklynnsDad folds.
** Dealing Turn ** [ 4d ]
Pasterbator checks.
bjuliano checks.
** Dealing River ** [ Ks ]
Pasterbator bets [300].
bjuliano folds.
Pasterbator does not show cards.
Pasterbator wins 910 chips

The flop call made me think he was on a flush draw. Now, knowing this, is the best move to check (like the flop bet was a continuation bet) and induce a bluff or bet again and make him pay for his draw. I think this is one of my biggest problems. Any help is appreciated.