Good posture is more important than pleasing your mother. A lifetime of bad posture basically ensures spine complications, back pain, muscle aches, and other not-so-pleasant physical health problems.
So how about taking a literal stand to improve and maintain a good posture for the rest of your life? Stand straight and get someone to make a duct-tape X on your bare back. Anytime you start slouching, the duct tape will start tugging at your skin and give you a slightly painful reminder to keep your back straight like your mother said.
If duct-taping your back is simply out of the question, you can try other simple tricks to maintain a good posture. Visualize an invisible balloon tugging up your spinal cord anytime you find yourself slouching. Exercise your core muscle groups and practice yoga. Invest in a standing station.
Also, people with good posture naturally exude more confidence. More reason to always walk like you have a book balanced on your head.
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