Never paint with a dry roller, indeed

I went to Ace this morning to get some paint. I'm basically color blind, so I brought in a swatch of fabric and forced the Ace employee to find me a color that matched and/or accented. He picked out Limesickle. I told him the room was 12 x 10 (meaning 2 walls were 10 feet across and 2 were 12 feet across). He told me I needed 2 quarts of paint, which he quickly mixed up for me. Anyone who has painted before or doesn't have a learning disability in spatial relations like me will quickly realize this is not enough paint. So I get halfway through my little adventure, go back to Ace, and discover that I have to buy a gallon of paint (because one more quart wouldn't be enough). As I was painting, I kept thinking of my friend who was forced to helped me paint my bedroom in Miami, who gave wise but repetitive advice: don't paint with a dry roller. Yes yes, I know. But I still ignored it today. Plus I was clearly running out of paint early on so I was trying to make it go really far. After a few sweaty hours of masking and painting I stepped back to admire my handiwork. And... there were big patches of white showing through because I didn't keep the roller wet enough. I hate being wrong.