Through the years, I have attended a few weddings, only one funeral, and several small parties that have all had some sort of celebratory speech involved. Though I cannot remember a time where I have been asked to speak like this, there are times that I can remember had both good and bad speeches.
At my second cousin's wedding, I found myself struggling through a series of long and not entertaining speeches. For the amount of people there, it was no surprise that not everyone had the same connection to the bride as one of the friends who was speaking did, and it took a draw on the ceremony. Long stories and details that I couldn't relate to bored me and made me even more hungry as I waited in agony for the food. The speeches were heart felt, but were so long that I, nor a lot of people, really cared much by minute ten after three people had already spoken.
To contrast, those speeches that have been short, sweet, and to the point have been my favorite. A short toast to a loved one at a birthday celebration. A sweet speech that summed up the love that two have shared, but got to the main point quick. Those have been the most successful in my view.