I think some people may want to boast. Part of human nature, can't say I'm immune from that.
Different people budget differently. For example, I can honestly say our grocery budget is $80/wk. Does that mean we never spend more than $80/wk on food, or even average $80/wk on food? No. We also budget $20/wk on restaurants (we can dip into the restaurant budget to buy more groceries), so that's up to $100/wk on food. My wife and I each get a $50/mo (about $11.50/wk) allowance...er...misc. spending. She's used hers on groceries more than once (and I've used mine on fast food more than once), so we're up to $123/wk max for food. Wait...what if we go to the movies and buy popcorn and candy? That can come out of our $50/mo entertainment budget, or our $50/wk date night budget if it's just my wife and myself.
I don't track quite to the penny, so I can't say for sure what the average amount we spend on food per week is (heck, if on a cruise, how much of the fare should I allocate to meals?). I can honestly say that we budget $80/wk for groceries, and another $20/wk for restaurants. If I tried to put enough disclaimers to satisfy everyone...it'd take me an hour to type up a simple "$80/wk for groceries, another $20/wk for restaurants" post.
BTW, for vacations we generally don't have a strict budget (tried doing that, wife not too happy). So our actual restaurant spending probably exceeds the $20/wk figure. For our accounting, vacation expenses (including restaurants) are counted as a vacation expense. For budgeting purposes, I deduct the normal budget amount for those categories (i.e. for a one week vacation I will deduct $80 from groceries and $20 from restaurants, that way we don't double-dip).
Recently, when I'm thinking of finances, I think of the figures as "how much to live our regular daily lives", "extra non-essential spending that can easily be cut (i.e. overseas holidays)", and "saving for retirement". The "saving for retirement" category is roughly equal, if not more than, the "how much to live our regular daily lives" category. I wouldn't claim to be saving at least 50% of our total income, but I might say that we're saving an amount equal to live our day-to-day lives (excluding expensive vacations). Even our retirement goals reflects this thinking; goal #3 allows us to live a somewhat extravagant day-to-day life, but the vacation spending will need to be restricted to one-week in the same country.
It's been a couple years since I ran all the numbers, and things have changed since then (we have an extra kid which would cost more, inflation which would cost more, we've reduced day-to-day expenses which costs us less, ACA should help keep costs down, etc.); but last time I checked, $24k/yr would have us living our normal day-to-day life in the US, with no cutbacks (this is our final retirement goal, #4).