The siren call of 'just one more trade' after a good run

My biggest mistake has always been the 'one more trade' after a solid winning streak, particularly around major data releases. I'd hit my daily or weekly target, feel invincible, then see $EURUSD or $GBPUSD start to twitch ahead of an NFP release, convince myself I could scalp 'just a few more pips,' and then proceed to give back a substantial chunk of my profits because I stopped respecting my risk parameters and started chasing.