Seeking signs and wonders (including tongues) is really a form of grumbling and complaining to God. What do you mean you may ask. Okay, I'll tell you.
In Numbers 11, the children of Israel complained and grumbled about the constant diet of manna. They weren't satisfied with what the Lord had provided for them. They still had one foot in Egypt. This angered the Lord and this was His response:
"Therefore the Lord will give you meat, and you shall eat. You shall eat, not one day, nor two days, nor five days, nor ten days, nor twenty days, but for a whole month, until it comes out of your nostrils and becomes loathsome to you, because you have despised the Lord who is among you, and have wept before Him, saying, 'Why did we ever come up out of Egypt?' "—Numbers 11:18-20
For many, God's word isn't enough. In the day to day of things they become bored and need more; they need a jolt of adrenaline. The reason for this, I believe, is because they're not sold out 100%. They still have worldly desires; God's word and the simple gospel by itself is boring.
"Now he who received seed among the thorns is he who hears the word, and the cares of this world and the deceitfulness of riches choke the word, and he becomes unfruitful."—Matthew 13:22
God's word is sufficient. If you're bored and want to complain to God that you need more, it's just evidence you still have a lot of the world in you.
"Not everyone who says to Me, 'Lord, Lord,' will enter the kingdom of heaven, but he who does the will of My Father who is in heaven. Many will say to Me in that day, 'Lord, Lord, did we not prophesy in Your name, and in Your name we cast out demons, and in Your name we did many mighty works?’ And then I will confess to them, 'I never knew you! Depart from Me, you who work iniquity!' "—Matthew 7:21-23
"Remember Lot's wife."—Luke 17:32