While there are plenty of letters, the letter "P" is a pretty important letter. Without it, we wouldn't have the adjectives "pretty" or "plenty," for example. It is a letter that created some confusion in the alphabet world for a while: the Phoenecians, who created the pictoral alphabet after the old Egyptian hierogliphics got confusing, and actually had two letter P's. One of them looked similar to the P we know now, but the other looked more like an upside down J. Then, when the Greeks modified the alphabet, they used the "P" letter to symbolize an "R" sound. Fortunately, the Roman's came along and perfected both the shape and sound of the "P" we know today. Now, we can use the letter "P" to form lots of different adjectives that we use every day.
"P" can be sort of a confusing letter, because it doesn't always make a reliable sound. Maybe you've heard the joke about the letter girl who really had to use the bathroom, but the teacher made her say her alphabet first. She did, only she made 1 little mistake- she said LMNOQ, leaving out the "P." When the teacher asked "where is the "P"?" the letter girl said "running down my leg." Well, that joke is a play on the fact that the letter "p" sounds like "pee." However, the letter "P" can also sound like "puh" if it is followed by a vowel (pancake). To make things even more confusing, the "P" can sound like an "F" sometimes, when it is followed by an "H" (phone, phonics). Finally, the "P" sometimes is silent and has no sound at all (psychology).
There are lots of different adjectives that start with the letter "P." In fact, some might say that P is a powerful letter used to make plenty of adjectives so it is prudent to know your "P's." It might be a pretty fun game in fact to try to name all of the adjectives that start with the letter P. For now though, here is a list or 20 pleasant and positive adjectives that start with P.