One of my favorite things to do as Pyro is hold my Flame Thrower on Spycicle + Dead Ringer Spies after their knife melts because they expect me to switch weapons and be able to feign, instead after their fire invulnerability period wears off they just catch on fire while feigning and I can easily chase them down without playing the Lost Woods game
Of course this strategy also has an unintended side-effect

Like yeah, using my primary weapon and not falling for the bait is somehow
my fault

I love this thing