Clothes don’t fit. If pants fit at the waist, they’re too short. If they’re long enough, they’re too wide. If a jacket fits your shoulders, the sleeves are too short.
If you’re really skinny, your alcohol tolerance is low. (This gets better as you gain more weight.)
Furniture isn’t designed for you, so you never quite feel comfortable in a chair, at a table. This is especially frustrating with public transport.
If you’re bony, it hurts your butt when you sit. It hurts your back when you lie flat on the ground, or you sit in a hard-backed chair. You gotta do some heavy squats to start packing on some meat, but if you’re going to the gym…
Gym challenges. If you’re new to the gym, and you go to the squat rack, the rack is set too low. So you’re going to have to adjust the height. If you’re sharing with somebody else, you’re going to have to adjust between every set.
If you’re tall, doing squats and bench presses are both harder for you than they are for most people, because of the physics of having long limbs. (This is the real reason why olympic bodybuilders tend to be short, and the source of the myth “bodybuilding stunts your growth”).
You hit your head on things more than most people.
You’re likelier to have your lung collapse.
You don’t look very masculine. This has repercussions in a bunch of areas – how other men treat you , how attractive women find you.
Center of gravity is very high, meaning you’re easy to knock over.
If you have a substantial height difference with your SO, kissing and hugging is always a bit of a stretch.