6'3" over here.
When I don't spread my legs, my knees touch the seat in front. If the person in front tries to recline, they feel resistance, they push more. No move. They slam into the seatback. It hurts me and it doesn't let them recline.
When I spread my legs to avoid the backseat in front, now this is the vicious part... Their seat can recline, but if they lift their armrest, the back of the armrest jams into my knee, with force amplified by leverage. Really painful.
Nowadays on longhaul flights I lean over and apologize ahead, sorry sir/ma'am, if you feel resistance when you recline, it's because your seat is hitting my leg, please don't use force. Some are unhappy. If so I apologize for the inconvenience but I don't control the length of my legs.
Basic courtesy would require you to check that it's safe to recline.