CNBC's Jim Cramer reminded viewers on Thursday that he doesn't like to distract himself by second guessing things.
"I always say there's no room for 'woulda, choulda, soulda' in this business ... Always think forward—eye on the prize—never backwards," the "Mad Money" host said. "But at the end of a fabulous month capping off 10 straight weeks of gains, even when we pull a little back today ... I can't resist."
Cramer ran through a number of stocks that he's kicking himself over for letting them get away.
After trading long in the 1970s and 80s, Cramer said, Eli Lilly has received a string of good headlines in recent months. It defended its diabetes drug against competition, released a product for migraines, and most recently paid $8 billion in cash for Loxo Oncology last month.
The stock has gained less than 10 percent this year and more than 63 percent over the past year.
"I know other stocks have roared more than this one, and I've been pretty consistent in liking Eli Lilly, but the stock never should've been so low in the first place," Cramer said. "It was always safe and well-run and I should've been pounding the table every single day on Lilly."
Cramer said he also should've pushed harder on Twilio, the cloud messaging platform that serves companies like Airbnb, Lyft and other small companies to keep in contact with customers. Twilio's revenue has been gaining steam as it loads on more and more clients, he said.
The stock has gained steam as well, adding more than 36 percent in the last two months and more than 256 percent in the last year.
Intuit, the company that owns Quickbooks, is one stock that Cramer said he told viewers to buy $162 last year. Now he's kicking himself for not pushing it harder, he said.
The stock is now selling nearly 50 percent higher than it did a year ago. It dipped Thursday to close at about $247.
Cramer said he likes Etsy, but should have thought differently of it a year ago. When the stock was at $20, the online marketplace made a move that worried a lot of investors including the host.
"But this is a company that raised the price of its service and none of its customers balked. In fact, Etsy just garnered more business," he said. "So I should've been relentlessly pushing this terrific Brooklyn-based business. Instead, I was more enthusiastic about The Nets."
The stock price is up more than 181 percent over the past year.
Cramer said he was worried about Roku not because of its product but because of the competition. He thought that Amazon would destroy the video streaming service in a matter of time. But the streaming business is steadily growing as people cut their cable off.
"Around Christmas, when thousands of people were thinking about switching to Roku and the stock was trading at just about $25, why didn't I pound the table trying to tell you to buy? I guess with the stock at $66 now, the only thing I can say is kick me," he said.
When the trade war between the United States and China accelerated, many investors feared that Boeing would be in trouble. But it turns out that China needs those planes more than Boeing needs their business, Cramer said.
The stock is flying 36 percent higher this year.
"The bottom line: It's not enough for me to be occasionally recommending a great stock. That's why I am kicking myself tonight and only tonight. This is over after tonight," the host said. "These are companies where someone in my family uses their products, I love their managements, I believed in the story—I should've been recommending their stocks every night."