Q: I have a lot of good ideas on how to do things and ways that our work can be improved. But people are telling me that I seem like a know-it-all. I can't believe that I seem arrogant; what do you think is going on?
A: It's time to take a step back and re-examine your interaction style.
The inner game
Defenses go up when our ways of being are challenged. In your case, it sounds like "being the smartest person in the room" may be interfering with getting along with people and getting things done. Let go of that persona, set aside your good ideas and let yourself relax. Focus on your breathing and exist just in the present moment — right now, there are no problems to solve and nothing you have to do. Notice what it feels like to just accept yourself and bring this feeling into thinking about your situation. Don't rush … this is an important part of the process.
Now, think about your everyday interaction style. How similar or different is it from the relaxed self you just experienced? What stories do you tell yourself at work? That "without you, things would fall apart"? That "no one else knows quite as well as you do"? Or even, "if I don't have the answers, I'm not valuable"?
These types of inner messages are fear triggers. If your sense of self-worth is driven by having good ideas (and having them validated by others), this could drive behaviors that others find unpleasant. And it could be hazardous to your health if it causes chronic anxiety, which seems likely.
More tactically, how often do you let others speak first in meetings? What do you do to validate others' contributions? Are you an interrupter? If you don't know, ask someone to observe you in a meeting. Clearly there are people who are willing to give you feedback, which, incidentally, you should regard as a very generous gift. And think about whether you'd like yourself much if the tables were turned.
The outer game
Decide what your goal is. Do you want to change your behavior so that you are no longer perceived as a "know-it-all"? If you don't, rest assured that the negative impressions you're giving will continue, and will probably become career-limiting.
To move forward, focus on one behavior, for example, that you'll let others speak up before you voice your opinion. Consider the barriers you might encounter.