My parents were fairly frugal when they were younger, but in weird ways. For example, they often told the story of how, when they were first married and saving for a house, they would keep the heat turned down and spend the evenings watching TV in bed with boxed mac and cheese because their waterbed had a heater.
From my perspective now, I'm baffled by (1) having a waterbed instead of a regular mattress (those were the more expensive option in the 70s/80s, right?), (2) using a heater instead of more blankets/warmer clothing, and (3) boxed mac and cheese as the epitome of "cheap".
I'm a bit more forgiving of the food stuff because they both come from cultural backgrounds where "real food" means meat, and rice and beans are "weird ethnic options", so boxed mac was probably the cheapest thing they knew of to eat.
Through my teenage years through today, they slowly moved towards Bogleheads-style spending. They've been FI for at least 5 years, probably closer to 10, but Dad loves his job, so he keeps working. Mom always worked part-time until she got laid off in the recession, and she hasn't tried too hard to find anything else, but doesn't call herself "retired".