I understand what you mean about the gas and am still want to say "ouch!" with gas prices being what they are, and even after nine months of retirement.
But to answer your question, not expense---EXPENSES. Within a couple months of retirement:
* cat became very ill with a urinary tract blockage---bill $1000
* husband lost weight without trying---led to a colonoscopy, endoscopy, barium study---
of course this happened right after he started his new insurance with a higher deductible, so $3000 to $4000 there
* toilets started leaking---a few hundred dollars to replace them (and then we moved shortly thereafter)
* we decided we could no longer stay in the condo we had lived in for 20 years and had planned to stay in indefinitely (too many renters and young people with their 3 a.m. partying, property not being kept up), so we had to spend several hundred dollars to move and then bit the bullet and realized that we could no longer remain in bargain-basement housing, and moved from a $125K condo to one double the price.
We've always had this little black cloud over us and weren't surprised that all hell broke lose right after retirement. It was unnerving but everything has worked out (kitty and DH okay) and we love our new place. It was a bumpy ride but we fastened our seatbelts so to speak and survived, even thrived!