I agree with Op that being comfortable means your income allows you to cover your housing costs and bills, plus to be able to make the kind if purchases she mentions, without having to give them much if any thought,in terms of overall budget.
£60k will allow some people to do exactly that if their housing costs and costs of things like childcare aren't excessively high. Because some people have much higher housing and childcare costs, £60k could be swallowed up by those things leaving nothing for the extras Op mentions such as replacing shoes when worn out, without a thought for the cost, having meals out or coffees etc.
We all know there are lots of people whose income doesn't last to thee nd of the month and are choosing between food or heating and that replacing a pair of shoes is just something there won't be money for without sacrificing some basic essentials. We know there are people who can never have a coffee out because that £2.50 is what they spend on feeding a family of 4 for a day. That's being not comfortable.
Lots of people are pleased and feel comfortable with some 'luxuries' that seem small fry to others. They feel comfortably off when they can choose freely innthebsuoermarket rather than looking at prices, say yes to an invitation to lunch in a restaurant without considering if they can afford it, can have a couple of holidays a year and know they can provide as many presents for children's parties as their kids get invited to. They feel they are able to participate in society and enjoy the things that make them happy and don't worry about a big expense like needing a new boiler as they have the money to pay for it.
Others pooh pooh this stuff. They say they don't feel comfortable unless they have their kids in private school with the fees for the next 6 years accounted for, plus enough money to live for 3 years if high paying spouse loses job. They don't feel comfortable unless that can ski each year or replace their big car every 2 years or live in the big detached house in a very expensive area.
Of course a lot is about what you are used to. Once you have more and bigger, it's harder to feel pleased with less and smaller. That's part of the problem isn't it...that lots of people need so much to feel pleased or comfortable. Once you develop an expensive lifestyle many of those things feel essential and the idea of not having them is shocking and the kind of income that wouldn't provide them seems pitiful or 'meh' as people mention. Some people only feel comfortable with an income that delivers luxury and things they know most people haven't got.l.so they need to feel they have much more to feel comfortable.
So Op, if your housing costs remain at around £1k, and you're able to cover your other costs and put some aside for old age or a rainy day, then I'd say your income is good enough for you where you live to feel comfortable. And I'm glad it covers your costs and gives you financial freedom to enjoy a life that isn't beset with money worries.
Lots of people have far less and feel comfortable too. Lots have far less and aren't comfortable by any means. But equally lots of people have double or triple what you do and sadly don't feel comfortable. There are always threads on here about people with incomes far in excess of yours who don't feel financially secure or comfortable..either because their debt (including mortgage) is so high, or their list of 'essentials' is so big that nothing is left.
Being happy with what you have is both a luxury and an art. There are objective numbers about what we need to survive and escape poverty and we probably come up with numbers about being comfortable too (Pension websites talk about incomes needed for a basic retirement, a comfortable retirement and a luxurious retirement) but feeling comfortable is also a mindset beyond those numbers. Feeling comfortable and satisfied and content with what we have is a great thing....so I'm glad you are able to feel that way and I think it's a shame that so many people couldn't even begin to envisage feeling comfortable with income, even if theirs is currently higher.