I give a small gift (hand cream, soap, homemade jam) to my immediate supervisor for Christmas and have never thought everything of it—but I don't feel obligated to do so. She's an incredibly sweet woman who has really helped me learn the ropes of my field (and has always given me a Christmas gift or flowers on my birthday). I work at small family-run company and have been here since the start, so most of us are quite close. Co-workers will often exchange gifts if they are friends with one another (or if one was covering for another while they were out on medical leave). I also will bring in homemade cookies/candies for the office, as do other people. However, I would not give a gift to the company principals (which includes my highest up boss/former supervisor); we don't have that kind of relationship.
$168 may not seem laughably low to those of you in the DC/SF area, but the MTA and its policies affect more than just the NYC subway and bus system. When MetroCard fares go up, so do ticket prices on MetroNorth and the LIRR. And there are a lot of people who rely on those trains to get to work every day. The LIRR is the busiest commuter rail system in the country, and I imagine that the vast majority of its 300,000+ daily ridership are commuting to or from the city. One-way peak tickets cost from $8 to $27 depending on where you live on Long Island; off-peak tickets are more like $6 to $20. Depending on the amount of time you spend in the city (or if you live there and do the reverse commute, like me), you may end up having to buy monthly MetroCards on top of your monthly LIRR (or MetroNorth) tickets to do a daily commute of around an hour. $112 for MetroCard + $325 for monthly LIRR ticket from zone 9 to the city = $437 down the drain every month. It's that or deal with the traffic on the Long Island Expressway every morning and evening, and as someone with serious car anxiety, that's not a very appealing option, either.
I would say that my girlfriend and I spend an average of $45/week on groceries (not counting household supplies). Looking at everyone else's responses, that seems absurdly low, but I think my numbers are accurate (and we're not malnourished). There are only two of us, no pets, and we live in Queens. We foot the grocery bill on alternate weeks. She doesn't use Mint (working on that), but I'm pretty sure that our grocery spending is similar. I love food and cooking, but we are thrifty people. We generally cook two large meals that will last us through the week, and then we'll go out to eat or get takeout once a week. We usually make sandwiches for lunch or bring leftovers to work. I don't drink, and my girlfriend doesn't like keeping alcohol in the house, so that certainly saves us money. We also tend not to have juice/soda in the fridge, and our meat consumption is pretty low. When I look at my grocery haul each week, there are not many luxury items. This year we bought a half-share with our local CSA ($287), which will hopefully provide the majority of our produce from the end of May through November. That comes to around $24 worth of vegetables every two weeks, which is more than we typically spend, but that's a luxury that I was willing to pay for. I'm also hoping that it will force me to be more creative in the kitchen! Mmmm, veggies.