Lampard spent the final months of the 2022/23 season as caretaker manager at Stamford Bridge.
And speaking to Sky Sports, the Blues legend concedes he was left unimpressed with the experience.
"I saw things that I know cannot be right at elite football and that's the truth," Lampard said.
"I didn't love working in that short period because it's hard to lay down an idea when you're going to be leaving but Chelsea will always be a massive club in my life.
"But when I understand the standards of Chelsea - in that period of time a lot of players were in transition of maybe leaving and some problems and motivation were a problem - in an interim period you can't really affect that.
"When you see the results of it, I'm experienced enough to know what's right and what's wrong and basic things in a training ground on a pitch.
"I didn't learn anything tactical but it did reinforce my beliefs of all my experiences of when you know what a group is really fighting in the same direction - how strong that can be and when it's not, it can be really challenging."