Peter is one of the most revered and respected of the Apostles and leaders of the early church, but he was not always a good example of how to lead or behave. We can learn just as much, if not more, from Peter's failures than his successes.
In Matthew, Jesus walks on water. Peter's first reaction is to ask Jesus to command him to come walk on the water too. Peter is able to do it at first until he notices the strong winds and starts to sink. It takes Jesus to come and save him.
Both Mark and Matthew show Jesus telling His Disciples that He is going to endure suffering and die before rising on the third day. Peter rebukes Jesus for saying such, to which Jesus responds, "Get behind me Satan!" In both Gospels, this is immediately after Jesus has just applauded Peter for knowing that Jesus is the "Messiah, the Son of the living God."
All the synoptic Gospels include a story of the Transfiguration. In both Mark and Luke, Peter responds, "it is good for us to be here. Let us make three dwellings, one for you, one for Moses, and one for Elijah." In Mark, we learn Peter says this because he was afraid, but in Luke, we are told that Peter said this "not knowing what he said."
We should also not forget that Peter at the Last Supper claims he will follow Jesus even to death, to which Jesus tells him that "before the cock crows" Peter will have denied Him three times.
In all these examples, Peter acts first without thinking. Doing so always ends disastrously for him.
It is good for us to be "doers" and put ourselves out there, but think before you do so. You could avoid the same embarrassment Peter faced if you remember to think because you act.