Merry and Pippin have one of my favorite friendships ever. They're an amazing team and provide a lot of humor and good plain hobbit-sense. How? Well, I'm going to do as Eowyn did in her earlier post and take a look at them both individually and together.
Merry is cool-headed, experienced, rather wise, and not afraid to speak his mind if it needs to be said. He can be somewhat cold and cautious on occasion, but more often than not he turns out to be right.He's loyal, brave, responsible and has a lot of character and willpower, as well as being very sensible. (His real name also happens to be Meriadoc, which I find rather fun.)
Pippin is pretty much the opposite of Merry. He's naïve (well, not always), somewhat reckless, gives into temptation easily, and tries to stay on everyone's good side. However, he definitely isn't all bad, or even part bad! He's smart, quick-thinking, humorous, and always optimistic. For example, his “group” is facing the entire army of Sauron, and this is what he says:
“We’ve got the White Wizard – that’s got to count for something!”
And of course, he's right- he's never unreasonably cheerful, and he can recognize the gravity of a situation most of the time.
Now, how do they do both together? Extremely well, providing a mixture of comic relief and impressive bravery. They're very different; Merry plans ahead and Pippin takes things as they come, Merry doesn't like to take chances but Pippin doesn't think about odds, &c.&c. But this difference makes them a very good team. Merry keeps Pippin from rash schemes and scolds him when he does something that could endanger them (like the Palantir incident), and Pippin lightens up Merry and gets them out of several tricky situations.
They also care about each other deeply, like brothers. When Merry is badly injured while helping Eowyn fight the Witch King, Pippin finds him on the battlefield and, deeply concerned, immediately takes him to the Houses of Healing with no thought for his own danger.
However, it isn't all great acts of heroism and moral lessons. They can be hilarious too- their way ofpointing out the obvious, easy solution to a problem and their different views on the same subject always makes me laugh, as well as their ability to sit down and joke (and smoke a pipe) in the midst of danger and distress.
One of the things that illustrates their friendship extremely well in in The Return of the King. Merry has sworn himself to the King of Rohan (Theoden), and Pippin has promised loyalty to the Steward of Gondor (Denethor). The two leaders are somewhat on opposite sides, but Merry and Pippin, while still remaining loyal to their respective masters, remain friends. They tease each other about protecting their lords from the other hobbit, but inside, they know that they'll always be friends, no matter what happens.
Which leads to an interesting question (and off on a tangent...sorry!): if Merry and Pippin were in opposing armies, what would they do? Would they avoid fighting each other and just attack the rest of the army? Would they quit? Would they do something amazingly heroic and manage to stop the whole war (my personal opinion, hehe...)? I'm not really sure what they'd do, exactly, but I do know that they would never battle each other like that, because relationships matter a lot to them.
So that's why I like and admire Merry and Pippin and their friendship. They're willing to make huge sacrifices for each other and the other people they care about. They are a wonderful team, restraining and yet encouraging each other, but they're also brave and valiant when by themselves. I find this especially admirable, that although they want to get back to their hobbit-holes and tobacco, they're both willing to go through hardships and suffering for the cause of a friend.