Everyone is different, so how you (would) react to being a SAHM is very dependent on your own personality and your current relationship with work.
Personally, I chose to quit work to look after DD and have no intention of returning until she is in full-time education. I had a demanding though enjoyable career for several years, left that to travel for a while then spent a year or so teaching English as a foreign language - something I enjoyed very much and found fulfilling. Then I had DD.
I have never regretted giving up paid employment so I can concentrate on looking after DD while she is tiny. DH is currently a full-time student, so our income is very low. But we manage fine - it's not so difficult if you don't mind living in a modest way. We still have plenty of fun.
It's potentially dull to be on your own with a small child all day, but I make sure we get out the house and do something every day - toddler groups, visiting friends, play dates, even simple things like outings to the shops, the park or the library.
I find our life is highly social as I'm constantly meeting other parents and making new friends at the various activities or randomly when we're out and about. Once you factor in meals and nap time, the day usually flies by.
I actually feel hugely privileged to be able to spend so much time with DD and experience her learning new things every day and being able to delight in her company without the stress of having to fit in time at work as well.
It's definitely not the easy option, but I feel that no one could give me that time back with DD - they grow up so quickly. On my deathbed, I don't think I would ever say "I wish I'd spent more time working". On the other hand, in a different situation I can imagine saying "I wish I'd spent more time with the people I love, especially my children when they were growing up...."