Bring salted water to a boil in a large pot. Cook the pasta according to package directions. Angel hair cooks quickly! Be sure to keep an eye on it.
While the water is coming to a boil, put the olive oil into a large, hot skillet and swirl it around to coat the bottom of the pan. Carefully add the tomatoes and cook for 4 minutes, stirring occasionally. The tomatoes may bubble and spit at you! BE CAREFUL and don't hover over the pan. After 4 minutes, remove the tomatoes from the pan and set aside.
Add the butter and garlic to the leftover oil in the hot pan the tomatoes were in. Salt and pepper the shrimp and add them to the pan as well. Cook the shrimp until you can see the tips of the tails just starting to turn pink ( about 2 minutes ), then flip them. Cook for another minute, or until the shrimp are cooked through, and then remove them from the pan and set aside with the tomatoes.
Add the spinach and the crushed red pepper to the hot pan and stir to combine with the remaining butter/garlic mixture. Cook for several minutes, or until the spinach just begins to wilt. You may need to add a tablespoon or two of water to help the spinach wilt.
Once the pasta is cooked, drain it and return it to the pot it cooked in. Add the tomatoes, shrimp, the wilted spinach, plus the freshly chopped parsley and stir to combine it all. Drizzle the lemon juice over it all and toss to combine.