I have a 20 month old who is just a complete bundle of energy - constantly running around, playing with about 5 different toys at once. He hates being strapped in a highchair so eating out is hard work, he runs off unless he is either in your arms, in the pushchair or on his reins.
My friend has a 21 month old - she can sit in restaurants for 2 hours at a time and her DS doesn't bother, she can let him out of his pushchair in the town centre and he doesn't run off.
If me and DH take my DS swimming, we have to get ready in shifts and hand DS over to each other whilst the other one gets ready as DS just runs around the changing rooms and either back into the pool or into the main gym - my friend's DS just stays put and doesn't run anywhere.
Grrrrrr - it must be SO much easier parenting a child like that.