Was this a bad play or bad luck?

This was a semi loose table. This is villian's first hand, he'd just come in a few hands ago. I was thinking I'd take my chances with a K high flush and lost. His bet made me think he had two pair or trips. Is that a bad play or bad luck?

PokerStars No-Limit Hold'em, $0.25 BB (8 handed) converter

CO ($31.40)
Button ($3.60)
SB :#A500AF(Villian)/ ($11.75)
BB ($9.15)
UTG ($17.25)
UTG+1 ($47.30)
Hero ($5.05)
MP2 ($24.15)

Preflop: Hero is MP1 with 6[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/spade.gif[/img].
<font color="#666666">2 folds</font>, Hero calls $0.25, <font color="#666666">2 folds</font>, Button calls $0.25, SB :#A500AF(Villian)/ completes, BB checks.

Flop: ($1) 3[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">Villian bets $0.75</font>, BB folds, Hero calls $0.75, Button folds.

Turn: ($2.50) 5[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Villian checks, <font color="#CC3333">Hero bets $1</font>, <font color="#CC3333">Villian raises to $2.5</font>, <font color="#CC3333">Hero raises to $4</font>, <font color="#CC3333">Villian raises to $5.5</font>, Hero calls $0.04 (All-In).

River: ($12.05) T[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players, 1 all-in)</font>

Final Pot: $12.05

Results in white below: <font color="#FFFFFF">
Hero has 6s Ks (flush, king high).
Villian has As 9s (flush, ace high).
Outcome: Villian wins $12.05. </font>