The thing about seeing other LOs sleeping great out and about is you have no idea how they are at home. And if they are also a dream sleeper at night (now) you don't know how things will be in a year. Your gfs may all be struggling with sleep issues 6 or 12 months from now whilst you might have a fabulous routine.
I attended a free cookery class for mums and babies, only 2 of us attended, there was a member of staff to play with the babies in the other side of the room whilst we cooked. The other mum (same age baby) noticed her baby was getting tired, left the kitchen, walked across lay him down handed him a piece of fabric (not even his own lovey or blanket, just random fabric) and left him. In a minute he self settled and went to sleep. Meanwhile... I noticed mine was getting cranky and tired, I put the sling on, walked, rocked, jiggled, gave him his lovey, sang to him, used my most powerful forms of APOP and worked HARD to get him to sleep (whilst he fussed and cried). What I really needed to do was leave and get him home to his bed (where he would have self settled and gone straight to sleep) but with only 2 of us attending I felt bad leaving half way through so I gritted my teeth and continued the APOP. The other mum felt sooooooo sorry for me.
After chatting it turned out she could lay her boy anywhere for a nap during the day. But come night time he was impossible to get to bed and then awake every 2 hours. Every 2 hrs!! Now I felt sorry for her. Mine went to bed at 6.45, had a feed at 10.30pm (woke, nappy change, ate, straight back to sleep) and slept until about 5am/5.30am.
This is why people tell mums not to compare babies. We often don't know the full story when we see someone who looks like they have it easy.