By Paige Freshwater When it comes to travelling on a plane, you should always sit in your designated seat unless stated otherwise by a flight attendant. If you’re lucky, a fellow passenger might swap seats with you during the flight — but this doesn’t always work out. That’s exactly what one man came to learn after “stealing” a child’s window seat because “she wasn’t using it properly”. Speaking to Reddit, a woman shared how she immigrated from Jamaica to America when she was around 10 years old — and encountered one of the “rudest” men she’s ever met in her life. She said: “It was my first ti…