When I have those "I don't feel like getting dressed, but I still want to look cute" days, I throw on a pair of jeans and my trusty J Crew V-Neck T-Shirt and move on with my day. I chose a bold red lip and a sleeveless trench to finish the look.
Top: J Crew (here)
Trench: Forever 21 (old, similar here)
Jeans: Forever 21 (old, similar here)
Bag: Zara (old, similar here)
Sunglasses: Ray Ban (here)