"I'll get a visible 6 pack just by doing crunches!"
"I'll get a visible 6 pack just by doing crunches in this fancy <insert 'as seen on tv' ab product here>!"
"I'll get a visible 6 pack just by doing crunches in this fancy <insert 'as seen on tv' ab product here> while watching an instructional video!"
"I'll get a visible 6 pack just by doing crunches in this fancy <insert 'as seen on tv' ab product here> while watching an instructional video with my friends!"
"I'll burn off my fat hips by using this hip abductor machine" (mostly women)
... In short, any spot reduction BS
"I'll get stronger by going to the gym and doing the exact same exercises, with the exact same weight every week"
"I don't weight lift because I don't want to get big" (women)
"I'll lose weight by cutting this arbitrary product - e.g. bread - out of my diet" (mostly my mom)
"I don't need to do legs at the gym, I work them plenty from <fill in the random sport>"
"Abs are made out of a special kind of muscle, unlike all the other muscles in my body. I can work them every day with very high rep counts and I'll have great results"
"Ronnie Coleman <or any other steroid abusing body building monster> does <insert ridiculous routine that could only work for a steroid abusing monster>, I'll have equal success if I do the same"
"I'm a unique and special snowflake and proven method <insert name of proven workout technique, such as starting strength> doesn't work for me. I'll instead do <insert routine here that focuses entirely on bench press, abs and biceps>"
"Squatting below parallel is bad for your knees"
"I squat <insert ridiculous number here> pounds... In a smith machine". Alternatively, substitute any exercise for squat.