How not to bluff

I wasn't involved in this hand, but it provided another example of how NOT to play.

Full Tilt Poker Game #_: Double Stack $30 + $3 (_), Table 4 - 20/40 - No Limit Hold'em - 15:46:12 ET - 2007/05/27
Seat 1: (3,240)
Seat 2: (5,885)
Seat 3: (3,055)
Seat 4: (2,675)
Seat 5: (2,945)
Seat 6: (6,345)
Seat 8: (2,855)
Seat 9: hero (2,745)
Seat 4 posts the small blind of 20
Seat 5 posts the big blind of 40
The button is in seat #3
*** HOLE CARDS ***
Dealt to hero [5d Js]
Seat 6 folds
Seat 8 raises to 140
hero folds
Seat 1 folds
Seat 2 calls 140
Seat 3 folds
Seat 4 folds
Seat 5 calls 100
*** FLOP *** [2d Ts 4c]
Seat 5 bets 2,080

This was all but about 800 of his stack, and it was 5 times the size of the pot. That just screams out "weak." There's a huge difference between an over-bet that's all in, and one that's not quite all-in.

I suspect seat 2 would have still called the all-in with top pair. Wouldn't it have been better to bet about the size of the pot, then fold to a raise or check-fold the turn if he calls and you don't improve?

Seat 8 folds
Seat 2 calls 2,080
*** TURN *** [2d Ts 4c] [8c]
Seat 5 bets 640

Again, what was he saving the last 85 for?

Seat 2 raises to 1,280
Seat 5 calls 85, and is all in
Seat 2 shows [8h Td]
Seat 5 shows [5h Ah]
Uncalled bet of 555 returned to Seat 2
*** RIVER *** [2d Ts 4c 8c] [4d]
Seat 2 shows two pair, Tens and Eights
Seat 5 shows a pair of Fours
Seat 2 wins the pot (6,050) with two pair, Tens and Eights
Seat 5 stands up
*** SUMMARY ***
Total pot 6,050 | Rake 0
Board: [2d Ts 4c 8c 4d]
Seat 1: didn't bet (folded)
Seat 2: showed [8h Td] and won (6,050) with two pair, Tens and Eights
Seat 3: (button) didn't bet (folded)
Seat 4: (small blind) folded before the Flop
Seat 5: (big blind) showed [5h Ah] and lost with a pair of Fours
Seat 6: didn't bet (folded)
Seat 8: folded on the Flop
Seat 9: hero didn't bet (folded)