That's true. If you have watched both you can draw out similarities. First things first - the Characters!!!
Ross and Ted
You have to admit - both were kind of geeky and sentimental. The hunt for the perfect woman is similar except Ross had a number of failed marriages.
And the biggest similarity is the way they love - see how Ross looks at Rachel, just like how Ted looks at Robin. The swirly kind of love.
Both taught at the university - Remember Professor Galler and Professor Mosby.
One had his dinosaurs and the other had his buildings which they couldn't stop talking about.
Furthermore, have you seen the flashbacks- don't Ted's hair remind you of Ross's hair during college! And their college friendship with Chandler and Marshall!
Rachel and Robin
The love interests of Ross and Ted. The entire show is in the doldrums thinking wether they are getting together or not. The shows could very well be named as "Whose bride will she be?"
Monica and Lily
Lily was like a sister to Ted and Monica is Ross's sister. They both were the glue for the gang keeping them together. They both were always the hosts. Monica welcomed Rachel and Lily welcomed Robin to the group, Both were kind of freaky with the anger and obsessive behaviour. Both had been perpetually trying for a baby on the show.
Chandler and Marshall
The awkward goofy kind of boy with humor as a special thing. They are stuck in dreadful corporate jobs unless they find their true calling. They both have had no luck with girls but they find their one true love forever and ever.
Joey and Barney
Sorry but Barney is not 1% close to the charm of Joey although both were the Casanovas of the group. Joey had this easy charm whereas Barney had a made up over the top fake charm.
Also both made some weird words - wisdomous and possimpible.
But they missed the most interesting and wacky character - Phoebe. Oh come on she was the soul of Friends. Her ideas, ideals and quirks were the cherry on the cake.
And 'Smelly Cat' is just quirky of the highest order!!
Next comes the plot - six friends staying close together as roommates or neighbours in the New York City. That's evident in both the shows.
The setting of course - Central Perk from Friends and MacLaren's Pub from HIMYM. The centre of their universe. Both the groups had a particular seat or booth. Did you know that before Central Perk opened that place was a bar! Technically it's healthier to have a coffee place than a bar but caffeine is not so good either.
And the love angles and triangles...
Chandler-Monica and Marshal-Lily
The true kind of love.
Ross-Rachel and Ted-Robin forming the love triangle with Joey and Barney respectively. The on and off kind of relationship. The girls got their proposals from other guys but unlike Rachel who knew it was Ross, Robin had no idea seriously.
Also the plot where Lily gets to move to Europe for her art job and Rachel gets an opportunity to move to fashion capital Paris. And who do they choose love or career and they both had a baby in picture too!!
Sounds similar!! Yes a lot similar!! But Friends is like Coca Cola and all other are cheap imitations.
(Image source: various sites on Google)