My flight to Alaska was cancelled but they were able to get me on the last seat on the next flight. Isle seat in the last row, right new to the bathroom. And as luck would have it the woman in the middle seat was probably only 5 ft tall but easily over 300 lbs. As expected her boyfriend was rail thin and poor dude was pinned up against the window. She spilled into both of our seats. Nice woman who apologized profusely for being so fat. Other issue was basically I had to partially hang out into the isle which put my head even closer to the bathroom doors which was right next to me. I heard things I can't unhear and smelled things I can't unsmell. I swear one guy must be dying inside to have those noises and that smell come out of him.
When I worked for MDS Pharma Services, I was flying non-stop. I was the rail-thin guy in this scenario every freaking time... Pinned against the window with no recourse. I remember one flight where I had boarded, was sitting in my window seat. An absolute smoke show sits down in the aisle seat with the seat in between us empty. They're getting ready to close the doors and I'm thinking, "Sweet, I'm single, I'll shoot my shot on our flight". Right as the doors are about to close, here comes a sweaty 300+ dude barging onto the plane. Mind you, there were tons of open seats on the plane. The smokeshow and I had already started chatting each other up, but when I saw that, I said to her, "I'm sorry, but that guy is going to be sitting between us". She asked if I knew him and I said no, but that it's my luck with flying... Sure enough, he bumbles down the aisle to our row and wedges himself in between us... 300 pounds, sweaty, gay florist who talked the whole flight about his cats, regardless of whether or not you had your headphones in. It was pure hell...