Awful behavior

Is any one else’s toddler behaving absolutely horrendously? I feel like all he does is whine, throw tantrums, and do the exact opposite of what we ask him to do. He’s kind of a brat. He used to be the sweetest kid but ever since he turned two he’s a nightmare. I try to keep my cool, offer choices, be firm with my no’s and also offer yes’s, we’ve tried time outs, I feel like we’ve tried everything and his behavior is just getting worse.

He’s the brightest kid, has an incredible vocabulary and is so curious about the world, but quite frankly I’m embarrassed by his behavior and I’m at my wits end.