No regrets. I love my job and couldn't imagine myself doing anything else. Most pilots I fly with (Captains, I'm an FO) say similar things when I ask similar questions.
No two days are the same, I learn something new every day. Just got back from a 10 hour duty day. Flew with a Captain who is close to retirement, fantastic chap, extremely knowledgeable and had some amazing stories. Some minor system failures, ATC leaving us rather strangely positioned for an NDB approach (flown manually, in an A320, the autopilot is there if you want it, if you don't, press that red button). Enjoyed the day, drank lots of tea, ate some cookies, looking forward to doing it all again somewhere I've never been tomorrow
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