The tight reg who is visibly annoyed or tilting after a bad beat is a completely different player for the next 30-60 minutes. Their range widens, their bet sizing gets erratic, and they start playing hands they'd normally fold without thinking.

Why they do it

Even disciplined regs go on mini-tilt at $1/$2. It doesn't last long but it's real. The tell is usually in their body language - leaning forward, stacking chips aggressively, muttering. When you see it, adjust immediately.

The adjustment

Tighten your own range and let them spew. Call them down wider than normal. Don't bluff them - they're in call-off mode. Just wait for a hand and get paid.

What it's worth

Recognizing a tilting reg and adjusting correctly is worth $80-150 in a single session. Missing it and continuing to play your default strategy against them leaves money on the table.