This was a confirmation of what I always believed in, and also what other in our group believed in. When we say short prayers before affairs, there have been instances when people have asked me whether I was ashamed of praying in public. The answer is a resounding NO. I am not ashamed to pray, whether in public or in private. I just don't get the point of praying long prayers before affairs and meals.
Second, people are not there to hear me pray, they are there to eat the food or to participate in the event and eat thereafter.
Third, people's concentration tend to drift away from prayer after a minute or two. Yes studies show that the attention span of an average adult lasts a maximum of 20 minutes but that sustained attention does not last on prayers, trust me I know! And I know you know it too.
I have to admit that when someone leads a very long period of time, my attention tend to drift away and before long I would be daydreaming. Has that ever happened to you? Never? I guess I am alone in this then... But really it does tend to end that way right?
And lastly, when we pray too long we tend to turn people off, we give of a holier than thou aura that other people shun. Instead of people opening up to us, they tend to shut us out.
This is the reason why I would recommend that if you have to pray in a public event or gathering, keep your prayer brief. Reach out to people by mingling with them during the event not during your prayer. Your long (or very long) prayer won't do it for you. On the contrary, your long prayer may be the reason why they won't be there to mingle with during the event.
Of course there are instances when you could pray a long prayer in public, but these are exceptions, the general rule is you should keep them short. At least it is from my point of view. If you disagree, let me knoe and we could discuss your points.