The bird's eye view is really difficult.Something or the other always goes wrong with the body proportions.I avoid this view the most XD
Fish eye view can be very hard. Choosing what perspective is most effective depending on the situation can be even more so if you're a picky artist!
My gosh, the elusive underside of chin! It's true, that took me so long to wrap my head around...
For me it's from the ground looking up(or ant's eye view I suppose?) I always find it really tricky to get legs and arms looking bigger, and to draw underneath chins.
Also there's the fish eye view if that counts, for the occasional trippy scene xD
The most difficult angle for me to draw is viewing from above, because from below it's easy for me to use some perspective. But using perspective from above is hard, because I always make the legs look award and I make everyone look like their wearing business pants.
