I dropped 'down' to a new post last year after a breakdown and a period of serious illness. Previously had a stressful management job. I adore it.
I now work for a large supermarket in the most basic of jobs but I am so happy. I look forward to work every day. I now have my regulars, who I see almost every day and have zero stress.
Whilst its important to stretch yourself, you have to balance job satisfaction. I'm so lucky that I don't have huge mortgage/bills and that I can manage on what I earn. I realise that for many this isn't possible and I am fortunate.
I now realise though that money isnt everything. Stress damn near killed my husband last year, and would have definitely killed our relationship.
I am now that 'bubbly, smiley' colleague. Because I am happy. It's not false or because I feel I have to plaster a smile on - it's because I am. Sorry. This has veered so far from your OP.