Bhagavad Gita Verse 41, Chapter 11

sakheti matvaa prasabham yaduktam he krishna he yaadava he sakheti |
ajaanataa mahimaanam tavedam mayaa praamadaatpranayena vaapi || 41 ||
 
Thinking of you as a friend, I addressed you rashly as O Krishna, O Yaadava, O friend. Not knowing your greatness, I said it in this manner out of carelessness or also out of affection.
 
sakhaa : friend
iti : in this manner
matvaa : thinking
prasabham : rashly
yat : whatever
uktam : said
he : O
krishna : Krishna
yaadava : Yaadava
ajaanataa : not knowing
mahimaanam : greatness
tava : your
idam : this
mayaa : I
pramaadaat : in carelessness
pranayena : in affection
vaa : or
api : also
 
Arjuna and Shri Krishna were childhood friends. Growing up together, Arjuna never realized the divine nature of Shri Krishna’s birth. He had treated him as he would treat any other friend of his. Now, having understood his divine nature having viewed the cosmic form, he wanted to acknowledge his ill-treatment of Shri Krishna, and beg for forgiveness for all the times he had acted imprudently. After all he was Arjuna, whose name meant “one who is extremely straight-forward”.
 
In Arjuna’s time, just like in the present time, insults with respect to people’s skin colour or caste were quite popular. Arjuna recounts his insults to Shri Krishna where he used to call him dark-skinned, refer to his caste, or call him a friend instead of a more respectable title. And like any of us, his intellect knew that insulting anyone was not the right thing to do, but he did it anyway. Knowing this well, Arjuna owned up to his ignorance, carelessness and rash behaviour.
 
But Arjuna also gave another side of the story. Although he did insult Shri Krishna out of carelessness in some instances, there were other instances when he did it out of sheer affection for his friend. When there is affection from both sides between friends, it is totally acceptable to insult each other. Arjuna was going to ask for forgiveness very soon, and hoped that Shri Krishna would keep this side of the story in his mind.

Bhagavad Gita Verse 60, Chapter 2

yatato hyaapi kaunteya purushasya vipaschitaha |
indriyaani pramaatheeni haranti prasabham manaha || 60 ||
 
For the senses are so turbulent, O Kaunteya, that they forcibly seize the mind of a even a wise individual who perseveres.
 
yatatah : persevere
hi : for
api : even
kaunteya : O Kaunteya
purushasya : individual
vipaschitaha : wise
indriyaani : senses
pramaatheeni : turbulent
haranti : seize
prasabham : forcibly
manaha : mind
 
Earlier, we saw that if we have predispositions to objects, they will result in thoughts popping up in our mind. This will be true even if we are not near those objects. Some of us may raise an objection to this statement. We may ask: "As long as I control my actions, what difference does it make if I think about an object such as a chocolate cake? It won't matter because I won't eat it, Correct?"
 
In this shloka, Shri Krishna responds to the objection. He says that thoughts can catch us at a time of weakness, when we are least alert, and undo all of our self control. These thoughts are generated by our predispositions or vasanaas.
 
Vasanaas are like dormant embers of coal that burn stronger when the senses add fuel to their fire. They are the seeds of thoughts, or "thought generators". This means that self control of actions is effective, but only to a certain extent, because self control does not tackle vasanaas. It is like trimming a weed instead of uprooting it completely.
 
Another aspect is pointed out here. One may practice conquering one's senses for a long time. That person can become an advanced practitioner through years of diligence and perseverance. He may come to the conclusion that all of his desires and vasanaas have been vanquished. But the senses and the mind are extremely clever; they will wait for months, even years, and then generate a thought that can destabilize his equanimity in a second.
 
In summary, it is not enough to control our actions in order to maintain equanimity, we have to remain alert and watch our thoughts as well.