I understand what you're saying, Classik. There are times, when asked to lead others in prayer, I pray what I'm moved to pray, without adding in all the superfluous words that others tend to use to lengthen the prayer time. God knows your heart, and he knows your words. He isn't going to be offended if you're able to say in 2 minutes what it takes someone else to say in 20.
We each have our own prayer style, just as we each have our own talk style.
And if someone acts as though embarrassed because you don't run away with time while praying, that is an issue that person must contend. It's not your issue. Don't accept any self-doubts about the prayer time. Merely rejoice that you have a voice with which to pray, a mind with which to consider your prayers, and a heart that belongs to God.