I hear ya on all of the above. On the attire part, I realize people want to be comfortable, but seriously, look somewhat presentable people!!!
It's better to take less. Many hotels have laundry or laundry facilities, and bathing suits can be rinsed out and dried in the hotel bathroom. One can always buy an extra tshirt or whatever, especially if one is bringing goodies back......
The worst airport I have ever been in is Heathrow London.... 
I travelled to Europe 5 times with a bunch of women back in 2003-2005...a friend is a travel agent and she put together some really cheap trips. $2000 or less for 12 days. It was great! She can't put them together for under $3000 or more these days, even cutting the trips down to 7 or 9 days.
3 of them were tour bus deals, and 2 were just four of us. On the tour bus, I was allowed one suitcase - max size at the time, and one carry-on. On the other two trips, I was schlepping my own, and we were on ferries and trains, so we had 24" inch bags and backpacks. No laundry time on the tour bus, but we did find a laundry on the other two.
Prior to those trips, I was one of those packers that had a suitcase of mostly shoes, purses, toiletries.
And another of a different complete matching outfit for each day, I was going to be gone.
(What can I say, I want clean clothes!)
I was in a panic over what to pack. I learned that 2 pair of black wrinkle free khakis, 2 pairs of jeans, tops that could be layered, 2 or 3 sweaters that would go with all the tops, a multipurpose coat( the tour trips were in March), a very lightweight jacket, the sneakers on my feet (take up too much room in suitcase) and a pair loafers with non-skid soles (necessary for cobblestone streets) were all I needed. Since clean undies are a daily necessity, I took the worst ones I had, and threw them out as I wore them. I took M's holey t-shirts to sleep in, they too went in the trash. Same with socks. Toiletries were the mini-size, so that they could be thrown out too. I also bought those cheap washclothes that you can get that are like 10 for $5. (never saw washclothes in Europe
)As stuff went out, in went all the really neat stuff I bought.
The most important thing to take when packing "light" .... is a travel size bottle of Febreeze!!
The most important thing to remember....you want to look clean and presentable, but you don't have to "impress" anyone, 'cause you won't see anyone you know, or will ever see again...so it doesn't matter if you have the same top or sweater on every other day...as long as they smell and look "fresh".
