Why raising is usually the correct play ......

Check out this hand history. If I would have raised the flop, or the turn, all the money would have went in the middle. My read was big pair or top pair, and I was trying to make him think I was on flush draw. I didn't want flush to get there, so the river was actually a bad card for my hand. So best play would have been to get raise in and force him to protect hand. Raise on that flop could have also looked like flush draw, so best play all around.

Full Tilt Poker Game #5819527781: Table Laurel Ridge - $1/$2 - No Limit Hold'em - 19:16:40 ET - 2008/03/28
Seat 1: dejablue2006 ($144.05)
Seat 2: full_tilting ($320.05)
Seat 3: crsbnsh ($47.45)
Seat 4: littlebubble ($104.55), is sitting out
Seat 5: pokerace12 ($507.95)
Seat 6: Gerrold ($212.75)
Seat 7: WikiLiki ($217.30)
Seat 8: UTHorns8 ($87.50)
Seat 9: cambo76 ($70.40)
WikiLiki posts the small blind of $1
UTHorns8 posts the big blind of $2
The button is in seat #6
*** HOLE CARDS ***
Dealt to WikiLiki [8d 8h]
cambo76 has 15 seconds left to act
cambo76 folds
dejablue2006 has 15 seconds left to act
dejablue2006 raises to $6
full_tilting folds
pokerace12 stands up
crsbnsh folds
pokerace12 folds
Gerrold folds
WikiLiki calls $5
UTHorns8 folds
*** FLOP *** [8c Kc 4s]
WikiLiki checks
dejablue2006 bets $10
WikiLiki calls $10
*** TURN *** [8c Kc 4s] [Td]
WikiLiki checks
Kai Devil adds $200
dejablue2006 bets $10
WikiLiki calls $10
*** RIVER *** [8c Kc 4s Td] [3c]
WikiLiki bets $35
dejablue2006 has 15 seconds left to act
dejablue2006 has requested TIME
dejablue2006 calls $35
*** SHOW DOWN ***
WikiLiki shows [8d 8h] three of a kind, Eights
littlebubble stands up
dejablue2006 mucks
WikiLiki wins the pot ($121) with three of a kind, Eights
*** SUMMARY ***
Total pot $124 | Rake $3
Board: [8c Kc 4s Td 3c]
Seat 1: dejablue2006 mucked [As Ad] - a pair of Aces
Seat 2: full_tilting didn't bet (folded)
Seat 3: crsbnsh didn't bet (folded)
Seat 4: littlebubble is sitting out
Seat 5: pokerace12 didn't bet (folded)
Seat 6: Gerrold (button) didn't bet (folded)
Seat 7: WikiLiki (small blind) showed [8d 8h] and won ($121) with three of a kind, Eights
Seat 8: UTHorns8 (big blind) folded before the Flop
Seat 9: cambo76 didn't bet (folded)