Local garbage at Caesar's

You would think I would have learned by now. Every once in awhile I commit the offense of making a large reraise with the second nuts.

I have As5c which makes me the nut flush on the turn. Like a lemur, I check. The river is a ten of spades making a straight flush possible with Qs. I bet $50, fucktard makes it $100, and I go all-in with my remaining $200. I call him fucktard only because he took a full five seconds to call, five seconds which made me think I had won the pot. He then sheepishly turns over the Qs to which I say "Nice hand, next time don't slowroll, pig!" The local Las Vegas poker world is small and you can be sure I will get the opportunity to slowroll him back, not to mention the constant barrage of below the radar insults I will hurl his way.

But back to the gist. What's the point of reraising in this situation if I'll only get called by a better hand? I lost my stack, got slowrolled to boot, and have thus gained the painful learning reinforcement which will keep me out of trouble till who knows when.