Yeah I find that when people say they are strength training and find it boring, it's usually because they aren't challenging themselves with heavy weight.
I agree. Loading up a bar you're not sure you can lift... staring at it, prepping form, breathing deep, planning your move, then pushing as hard as you - safely - can... it's very engaging.
My problem is with the rest period, not the lifting part. I wait 90 second between each set, it's really annoying. I read a book usually, or browse HN, but it's a very "interrupted" thing.