hi,i struggle with the f chord with the index finger,both e strings[especially the high]on my tele.I have 4 other guitars-sg,330,sheraton,12 fret no name, that are a breeze to play. I asked my friend who sets lots of guitars up etc and he said to just play the bloody thing haha,now,i can totally see/respect his opinion but its doin my head in[the tele,not him], i try more pressure,less pressure,roll index,thumb adjust,wrist angle,tight against fret,in the middle-5/10 the e string dont play right,back to other guitars-piss easy f! Gotta be the nut or something right?